Eugeni's blog

Ivy Bridge programming manuals are now available

Jun 222012

Hi folks,

For everyone’s joy and amusement, Intel Ivy Bridge programming manuals are now available at the intellinuxgraphics.org site.

This time, the documentation is split across 4 volumes, and consists of 17 pdf files. Comparing with last year’s Sandy Bridge documentation release, there is 1 additional part focused specifically on L3 cache and URB, a specific section about GT interface programming, another part covering multi-format transcoder, a new section specifically for PCI registers and one additional section focused on execution units details.

For the ones of you not feeling like clicking on the very first link in this post, these are the contents of this documentation release:

If you always wanted to understand the internals of a GPU, learn about the amazing world of MMIO registers programming and have control over your GPU, this is your chance .

Have fun!

i915 in the 3.4 (and looking towards the 3.5) Kernel statistics

devel, english, intel, kernel, linux, programming, writing 4 Responses »

May 272012

Hi folks,

So, Kernel 3.4 got released a couple of days ago, and the merge window has reopened for the 3.5 Kernel release.

We have put lots (and I mean it!) of work towards making a huge progress in the Intel Linux Graphics kernel driver for the 3.4 kernel, but things look yet even more brighter for the next one – namely, 3.5!

As a picture speaks louder than 1000 words, I’ve done a simple chart comparing the number of changes in the drivers/gpu/drm/i915 directory over the Linux Kernel releases since the 2.6.30 release some years ago:

Linux Kernel commits rate between 2.6.31 up to 3.5.0 (so far)

Between 3.3 and 3.4 Kernel versions, we had an astonishing number of 152 commits related to the drivers/gpu/drm/i915 directory (e.g., the Intel graphics driver in the kernel). This number looks impressive – but it is pale if we compare it to the 343 commits we had so far for the 3.5 Linux kernel merge window

So far, we are just 2 patches away from the all-time high of the 2.6.37 Kernel – and we are just getting into the 3.5 Kernel development cycle yet.

In case it is easier to read the absolute numbers instead of graphs, here is the full picture, generated from the git log --oneline <<kerner_version>>^1..<kernel_version>> drivers/gpu/drm/i915 command, for all the kernels between 2.6.29 and 3.5 (up to date):

2.6.30  98
2.6.31  122
2.6.32  119
2.6.33  144
2.6.34  69
2.6.35  155
2.6.36  184
2.6.37  345
2.6.38  247
2.6.39  113
3.0.0   109
3.1.0   131
3.2.0   126
3.3.0   78
3.4.0   152
3.5.0(next) 343

I’ll try to cover some of the highlights of the next Kernel release in the next post (ppgtt? haswell? valley view? DRI1 ? RC6? I2C? VBT? Those are just some of the keywords) – but this kinda answers the question whether the Intel Linux Graphics driver is alive.

Yes, it is.

And it rocks .

April updates from the Intel Linux Graphics land

devel, english, intel, kernel, linux, mesa, wayland, x.org 1 Response »

Apr 302012

Another month is at end, and it looks like a good timing for another update about the Intel Linux Graphics project.

As usual, starting with Kernel, I can say that this way a very, very busy month, and we had more kernel patches during this time than I can remember from the past. Several patchbombs came through, such as:

Several rounds of Ben‘s patches for timed GPU execution, or BO waits. Those patches add the ability to specify the desired timeout parameter to the core GPU functions, and allow the userspace to specify how log to wait until they are done – instead of waiting for them indefinitely. It is a nice addition to the way userspace cooperates with the Kernel part for the GPU-related tasks, and a helpful addition to support the GL_ARB_sync OpenGL extension.
Also from Ben, we had some patches that fixed a couple of sparse warnings. They should not change anything functionality or performance-wise, but they make the driver code more elegant .
From Daniel Vetter, we had a 22-patch series for ~~dragon slaughtering~~ consolidation of the legacy DRI1 code paths. Those patches do a huge cleanup and properly split the DRI1 and DRI2 calls in a way that everything related to DRI1 should belong to the i915_dma.c module now.
Chris Wilson and Jesse Barnes have been working on a better way to handle the PCH PLLs separately from the display pipes. This patch greatly simplifies the interaction with the components of the GPU located on the chipset, and allows to allocate or re-use different PLLs on-demand. This came particularly handy for my Haswell enablement efforts, where most of the things are being done by the CPU part of the graphics subsystem, and PCH is used for non-essential tasks.
Also from Chris Wilson, we had a 28-patch series for reusing the stolen memory early in the GPU initialization. Stolen memory is being allocated by BIOS for its need, and previously, when Kernel GPU driver was loaded, most of the memory was re-initialized. With those new patches, it is possible to reuse BIOS-allocated objects and even allocate frame buffer from the stolen memory. Yet another step towards a faster and flicker-less boot!
Ben Widawsky has sent his patches for L3 cache remapping. Those patches account for the row-level remapping of cache content when a parity error is detected, and this task is carried transparently to the software. On Ivy Bridge (which those patches are targeted), this situation is detected by means of an interrupt, and when this interrupt gets to the i915 kernel driver, it is able to cope with it and keep track of the failed bits. In other words, you may think on it as on a some sort of badblocks handling which is used for hard disks disks, but for L3 cache. Except that the L3 errors are much, much rare to occur.
Some power subsystem refactoring came from me, where all the power-related components of the driver (rc6, watermarks, framebuffer compression, power monitoring and turbo-related bits) got moved into the intel_pm.c module; and Daniel Vetter has also complemented this new module with additional power-related items I missed in my original move.
As another major patchbombing, I’ve send another round of Haswell GPU enablement patches, which add a new intel_ddi.c module, improve support for HDMI outputs, and address most of the comments I’ve received for the past months about those patches.
And finally, still on Intel Linux Graphics page but on an entirely different hardware, Alan Cox has sent a round of updated kernel patches for GMA500 support to inclusion into the drm-next tree.

Besides those major patch series, we had several patches for i8xx interrupts handling and gen2 fixes (which also helps to answer the question whether the old i8xx graphics cards are still supported ), improvements in page flipping, turbo initialization, Sandy Bridge GPU hangs in Google Maps/Earth, proper IPS polling which should be limited to Gen5 architecture now, pineview clock gating and several backlight fixes, besides all the other smaller ones.

On 2D driver side, the major news of the past month was the release of Glamor 0.4 acceleration backend. The biggest changes are the support for DRI2 and texture from pixmap functionalities, co-existance with AIGLX, many performance optimizations for pixmap uploading/downloading, full GLES2 color formats support and a new texture cache pool mechanism to reduce texture/fbo creating and destruction overhead and considerable improve overall performance.

Still on the 2D side of things, a new Cairo 1.12.2 release went out. This is a largely bugfixing release, which fixed a large number of issues which were found out since the Cairo 1.12 got released. Chris Wilson has also carried out a performance evaluation of Cairo 1.12.2 with different backends in his blog.

On Mesa side, lots of bugs were fixed, as usual, and among the most interesting updates for the past months that I caught were:

Support for RGBX_8888 format used in Android native buffers from Sean Kelley.
Support for additional gbm interfaces from Ander, used to allow weston compositor to reuse KMS framebuffer objects instead of creating and destroying them for each rendered frame.
Addition of the DRI image v4 extensions to MESA_drm_image, and support for additional DRI image formats from Gwenole.
Also from Gwenole, 5-patch series for the DRI2 changes to add support for the new Wayland and VA/EGL proposals to handle YUV buffers, and differentiate progressive/interlaced contents.
A couple of fixes for mipmap offsets when used with HiZ and separate stencil buffers, from Paul Berry.
Lots of work on GLSL support, from Eric, Ken, Ian and Paul.
And finally, still from Gwenole, came a patch series to allow caching data regions according to a given offset.

Moving to Wayland, the patches that caught my attention were:

Collabora’s Pekka Paalanen‘s patches for adding Android support for Wayland (which were already covered by phoronix as well).
Ander’s patches for reusing KMS framebuffer objects.
Gwenole‘s patches that added support for querying for the list of supported surface formats, support for YUV buffers and generic buffer formats.
And Tiago Vignatti‘s patches for xwayland improvements, customizable modifier key biddings.

And, last but not least, we’ve gone through the list of the open freedesktop.org and kernel.org bugzillas, and managed to scrub dozens of fixes in the past few weeks, solving a huge variety of issues – from i8xx-specific bugs up to recent GPU turbo issues after idle on newer machines. If you have a bug open with us, take a look if it is still active – chances are that many of the issues you could have were already gone . And if it still there, it would be a great time to check it again and verify if the drm-intel-next tree is still affected by it. As Kernel 3.5 merge window gets closer, it is a very good timing to try to address the remaining issues prior to its opening.

That’s all for now – stay tuned for future news from the Intel Linux Graphics land, and enjoy the International Workers’ Day meanwhile – if your country considers it as a holiday, of course !

Mid-April updates from intel linux graphics land

devel, english, intel, kernel, linux, mesa, x.org 11 Responses »

Apr 142012

As Starks used to say, “Winter is coming”. So in this sense, time has come for another round of updates from the Intel Linux Graphics project.

This time, it took me less time than on previous round of updates, so I think I’ll be able to give you some more details about some of the most interesting changes I’ve spotted for the past weeks.

Starting with the Kernel, many and many patches has landed into the intel-gfx mailing list. Among some of the most interesting were:

Another round of Valley View enabling patches from Jesse Barnes. Some of both Valley View and Haswell architecture patches were already included into the drm-intel-next branch by Daniel Vetter, but obviously most of the things are still being worked on. Valley View patches are getting really close to their final form, but some of the changes come from the fact that its architecture handles most of the display-related operations in a very orthogonal way to the other GPUs we have. So we’ll still see more rounds of patchbombing on ValleyView front.
Daniel Vetter sent another round of patches for PPGTT handling, most of which were already included in his drm-intel-next tree by now. Besides those, Daniel came with another round of Sandy Bridge hardware-related workarounds for the kernel as well. None of those were (apparently) hit by our usual code paths in Kernel, but in order to prevent possible future problems it is better to be safe than sorry on this matter.
Jesse also came with a patch series which reworked and simplified some shared code paths in the driver, mostly related to the Display Port support and interaction with the PCH-based items (e.g., parts of the display that are based on the chipset and not on the CPU itself).
Chris Wilson sent some patches for properly handle some Graphics interrupts corner cases, some additional debugging patches, additional LVDS-related fixes and a large number of patches that improve the way GPU rings interact between each other.
Adam Jackson from Redhat, Rodrigo Vivi, Paulo Zanoni and Takashi Iwai from SuSE have been working on supporting new video modes that we weren’t handling properly (such as modes that are not properly described in EDID metadata that monitors report even when those modes are actually supported by them). Those patches resulted in a series of very interesting discussions about how to handle such cases as well, including all the scary terms like CVT, DMT, EDID, GTF2, GTF, ~~and all the other WTF-like terms~~ and all the related stuff.
Ben Widawsky posted some patches for proper cache-level parity handling and better RC6 visibility from userspace, by using the sysfs facilities.
Last but not least, I’ve sent out the 3rd round of Haswell enablement patches. Phoronix already did a great coverage of them in the past weeks, so as the major highlights of this new series is support of digital outputs (like HDMI and DVI), and some additional tweaks to make things work better in overall. This time, the patchbombing was of mere 29 patches thanks to Daniel Vetter who had already included around as many patches into his drm-intel-next-queued tree last week. It was an amazingly interesting experience for me to work on this hardware enablement, and it is great to see the results of this work out in the wild. And of course, I’d like to thank Jesse for helping me with most of the hardest issues I had, and Ben for his help when I got completely stuck on some of them .
And finally, still related to the Intel Graphics but also to all the other drm-based Linux projects, Paulo Zanoni have been working on an infoframes programming tool, which was finally included into the intel-gpu-tools suite; underscan properties support and on generic CRTC properties development.

Moving to Mesa, lots of patches on all the areas as well. The most interesting ones related to the Intel GPUs that I managed to look at were:

Eric Anholt’s work on GLSL 1.40 support and performance tuning in shaders for Intel GPUs. The GLSL 1.40 support is a big step for the open-source GL library, and it will be a very welcomed addition for the next GL versions support. And performance-related patches are always a nice thing to have .
Ian Romanick sent the patches that rework the initial uniform handling in Mesa.
And Neil Roberts came with some patches that improve wayland-specific Mesa code paths.

Besides those changes, we had hundreds of patches that I left out of the scope of this update. Lots of activities are going on on many Mesa-related development, and the progress of this open-source GL implementation is looking great!

On 2D driver side, lots of patches entered the xf86-video-intel project for the past weeks, mostly related to the SNA acceleration backend, but also some glyph-related fixes and other bugfixes for UXA. All of them came from Chris Wilson, who is doing an unbelievable job on the project for the past years!

On Wayland project, as usual, lots of activity was going on. Among the most interesting developments was the addition of piglit support to the project by Chad Versace, which allows to run the piglit tests under GLX, Wayland and X11/EGL while selecting the desired window system at runtime.

And finally, on a related project, Jeremy Huddleston has released the first maintenance release for xorg-server, which fixes many input-related issues together with some RandR fixes and small memory leaks.

I guess that’s it for today. Stay tuned for future updates, and enjoy the next season of The Game of Thrones meanwhile (which works amazingly well on my Intel-based card with vaapi acceleration by the way ).

Compensating for long time with no news with lots and lots of them

devel, english, intel, kernel, linux, Linux-Planet, x.org 7 Responses »

Apr 012012

Yeah, I know that it has been quite a while since I last time wrote about news from the Intel Linux Graphics land. But as an excuse for such a long delay, I can say that it wasn’t because we had nothing to comment about – but on the contrary, we had sooo many things happening that I really could get a free time to write something.

With so many happenings in the past weeksˆWmonths, it is hard to know where to start. But I’ll try to cover the most relevant events which happened since the last update.

As one of the coolest things which happened in the past month, I must mention the OSTS 2012 conference. OSTS stands for Open-source Technology Summit, and it is an Intel-internal (with some guests of course, among them, naturally, Linus Torvalds himself ) event which aims at gathering all the Intel open-source developers in one amazingly beautiful place between the states of Oregon and Washington. The event takes place in Skamania Loudge, one of the most beautiful places I’ve been to, and it happened on the first week of March.

While there, I finally had a chance to discover the rest of the team in person (yeah, it is really nice to have people faces matching the names who were just voices on the phone and irc handles in the past). And, of course, it was a huge opportunity to discuss many of the projects we’ve been working on in person (alongside discussing the politics, open-source, football, french history and pretty much everything else ).

Besides technical stuff, the conference itself was amazing, and it is great that Intel organizes it and makes it such a success – I really hope to be able to attend the future iterations of it as well.

But back to the news, let me cover some of the major highlights of the Intel Linux Graphics project which we had in the past month or so.

First of all, the 2012.02 Intel Linux Graphics stack release was released, bringing a full-featured Ivy Bridge platform support on the hardware side and OpenGL 3.0 compatibility on the software one. The support for GL 3.0 is a huge leap forward for open-source graphics landscape, and I’d like to congratulate all the developers who were working on it for the past months. You did an amazing job guys, congratulations for shaping the open-source world and making it move ahead in such a great pace!

One day after the 12.02 stack release, Chris Wilson has released xf86-video-intel 2.18, featuring hundreds of new commits and improvements. But the work on the 2D driver by no means stops at this point – we already have lots and lots of new commits there, most of which are related to the SNA technology. It is still considered experimental, but at the same time it is already quite ahead of the UXA backend in many trends.

Still on the 2D support side, Chris Wilson has also released Cairo 1.11.4 and, a couple of days later, stable Cairo 1.12 version. This is the first major Cairo version in years, and it comes with an amazing set of features and performance improvements in all aspects. Check those two articles on Chris Wilson blog for some of the highlights of those releases.

Moving to the kernel project, we have an amazing number of features as well. Within a couple of hours from each other, Jesse Barnes has published his first set of patches for the Valley View support, and I’ve sent my patches for Haswell enablement. Both series of patches has already received a couple of iterations of updates, and have already been covered by phoronix reviews. Another major step towards full Open-Source support in not yet released GPUs!

Still on Kernel, Daniel Vetter has released a couple of snapshots of his drm-intel-next tree, and initial patches for the 3.4 kernel has already landed in Linus Torvald’s tree. And yet, while the next version of kernel is still taking place, we already have a a huge amount of patches getting ready for the one after it – the 3.5 one. Among those, are the logical context switching patches from Ben Widawsky, gtt handling improvements, lvds improvements, more Sandy Bridge and Ivy Bridge workarounds, improved semaphores for display plane, enablement (hopefully final) of RC6 by default for Sandy Bridge, and many many others. Things are looking great, and the development pace is amazing. I’ll try to cover more details of those patches in one of the next blog posts.

And to finish with the Kernel side of the story, Dave Airlie has managed to nail-down the long-standing issues we had while suspending, which resulted in random filesystem corruption and other nasty side effects. The patch was already sent to Linus, so things on the suspend-resume side are looking sweet again.

On Mesa side, Eric Anholt has sent the initial GLSL 1.40 patches. GLSL 1.40 is a bit different from its 1.30 counterpart in the sense that there is not much use for it outside the OpenGL 3.1, which is not there yet. Meanwhile, Mesa 8.0.2 was released, with additional bug fixes and improvements in this stable edition of it. So far, Mesa 8.0 looks very impressive, from both stability and performance point of view. Once again, amazing job guys!

Besides those news, we had thousands of new patches meanwhile, which I won’t be able to cover in this post. The development goes on and on, and so far 2012 looks quite promising for the Intel Linux Graphics project.

And, last but not least, this probably will be my last post while I have 0x1E years of age. In a couple of hours, I’ll have to go through a bit-shifting in age, coming to a very nicely looking number of 0x1F years (which looks yet more amazing in binary, being represented by a beautiful number of 0b11111). Almost coming of age by now .

Another round of updates coming your way

devel, english, intel, kernel, linux 12 Responses »

Feb 162012

Another week has passed, and time has come to write some more updates from the Intel Linux Graphics land.

As the major news, as you all already know, Mesa 8.0 was released, bringing GL 3.0 and GLSL 1.30 support combined with multitude of fixes and enhancements all over the place. For Intel i965-based graphics cards, for instance, this means a very nice boost in performance (specially on Ivy Bridge platform), lots of stability fixes and, of course, complete GL 3.0 feature set.

Besides Mesa, Kernel project was also amazingly active for the past few weeks.

Daniel Vetter has updated his drm-intel-next tree, with a nice set of changes. Most notable of those is the support for PPGTT – which stands for Per-process Graphics Translation Table. In other words, this means that each process is able to map his own region of the GPU memory, and should not interfere with all the other ones using the GPU at the same time. This results in better performance (due to the reduced need to re-mapping addresses, and due to the fact that PPGTT entities are GPU-cacheable) and, of course, much enhanced stability.
This new round of patches also includes a much improved interlaced modes support. These patches represent a very nice thing in our open-source community – they started with a simple request on the mailing list, which then transformed into a bugzilla entry, and after weeks of Daniel, Paulo, and many other developers working on those fixes, resulted in a amazing series of patches which greatly enhances the support for interlaced modes in Intel GPUs. This is how Open-Source community works – and this is awesome!
Swizzling support for Sandy and Ivy Bridge architectures, which can also improve the performance for many use cases.
Lots of bugfixes and improved debugging support.

Besides those patches, the notable patch-sets of the past weeks were:

Ben Widawsky’s logical context switching patches. On a high-level overview of this feature, we can describe is at a feature which adds support for having a per-context set of GPU items the processes have access to. So it adds the possibility of having a different context id for each set of operations. This way, what processes in one context_id do should not affect the processes in another set. For GL_ARB_Robustness OpenGL extension, for example, it could prevent one WebGL applications from taking down all the other users of the GPU for example; and for GL_EXT_Transform_feedback it would allow each process to have a way to store its own feedback data for different stages of the pipeline – such as vertex shaders, geometry shaders, and so on.
I have sent some patches for RC6 feature debugging, and apparently they have solved all the remaining problems with RC6 support on Sandy Bridge. So hopefully, one year after the platform launch, its remaining ghosts are finally being put to rest.

On other projects, the most notable news I managed to catch in the past weeks were some xrandr patches from Bryce Harrington from Canonical, some DRI2 enhancement patches from Mario Kleiner and input and synaptics patches from Chase Douglas on the X.org development project.

And finally, on Wayland, lots of development activity has been going on as well – most notable patches were from Ander about drag and drop icons, and patches from Juan Zhao which added support for window maximization to the core protocol.

Time for some news

devel, english, intel, kernel, linux, mesa, x.org 1 Response »

Feb 092012

Time flies by quickly, and another couple of weeks has past. So time for your regular news from the Intel Linux Graphics land!

Starting with the hot topic of the past years, Wayland 0.85 has just been released! This release marks the first milestone in the road to a stable 1.0 Wayland and Weston release. After it, we’ll have a 0.90 release, which would be the one to mark API freeze and will begin the preparation to the final 1.0 release. Of course, additional releases could happen meanwhile. Wayland has evolved a lot for the past years, so make sure to check it out.

Besides Wayland, lots of activities have been going on with all the projects.

On kernel side, Daniel Vetter has sent out his new drm-intel-next tree, which features lots of fixes from Ben, Eric and Chris, improvements to swizzling handling, fence accounting improvements, VTd workarounds for Ironlake, simplified debugfs handling code and an improved i915_error_state logging.

Besides those improvements, lots of attention was directed towards interlaced modes support on Intel GPUs, which resulted in a large series of patches from Paulo Zanoni and Daniel Vetter that should improve support for interlaced and non-interlaced modes and made them, well, work correctly . If you have been experiencing any sort of problems with such modes, please, try the patches and verify if they solve the issues. Chances are that they will, but if they won’t, please, let us know!

Among other interesting patches in kernel for the past few weeks, Ivy Bridge hard-hang fixes are among the most notable ones. Those patches toggle a couple of work-arounds for issues which randomly affected some of the Ivy Bridge machines – and resulted in complete system hangs. Due to their random nature, and specially due to the fact that they mostly affected low-resolution modes (chances to hang your machine in a 320×240 resolutions were noticeable much higher than in any other resolution), we had hard time to track them previously. In fact, we only managed to reproduce them consistently in the last week – and luckily we were able to come with patches which apparently fixed most of the problems. The patches will probably be included into 3.3 kernel via the drm-intel-fixes branch, and if they won’t cause any other issues we’ll backport them to 3.2 kernel as well.

Another interesting patch is the one which applies the missed IRQ fix (a.k.a., the voodoo patch ) to Sandy Bridge platform as well. So far, we had a couple of reports which mentioned that a very similar issue to the one which was fixed on Ivy Bridge last month was happening on Sandy Bridge as well. If you are suffering from this issue, please, give it a try and let us know if it solved the issue to you or transformed it into anything else (like a GPU hang which happened on one of the machines instead of missed IRQ. Those results would be even more interesting, as they could tell us what we are missing and how to fix the problem for good).

Additionally, lots of development was targeted on improving the semaphores issues detection and avoidance, and for better debugging support in the i915_error_state log. Usually, this log is all that remains of a GPU hang – so the more information we can get from there, the better.

And finally, aiming at finally discovering what root-causes all the rc6 issues out there, I sent out a patch which allows to hopefully isolate the issue. Leann Ogasawara from Canonical was also kind enough to pre-build Ubuntu kernels with this patch – so if you are affected by a RC6 issue, and are running Ubuntu – please, give them a try!!

On Mesa side, things are moving very quickly towards the Mesa 8.0 release. The 8.0-RC2 version was already released, and final 8.0 version is expected to happen in a very near future. Who knows, perhaps by the time you’ll be reading this line, it will already be among us . Mesa 8.0 release looks very exciting so far – besides the GL 3.0 extensions and GLSL 1.30 support, it also brings amazing performance and stability improvements. Hopefully you’ll be able to see it with your own eyes when the next stable release will be out – or, if you don’t want to wait that long, or want to use your very last chance to report any major show-stopper bugs in the 8.0 branch – now is the time.

On the xf86-video-intel side, as usual, hundreds of patches were committed by Chris Wilson, mostly targeting the SNA backend, and also the Glamor integration. Since the beginning of the year, git log already shows 380 new patches. Out of those, 368 are SNA-specific for now. Phoronix has run yet another round of SNA testing in the past weeks with some interesting results. Things are getting very interested with this backend.

And finally, moving to the intel-gpu-tools project, two new tools were proposed in the past few days – one for testing different panel fitter settings (intel_panel_fitter, from Paulo Zanoni); and another to demonstrate the sprite features, available for SNB/IVB platform, which uses 3 new IOCTLs included in the latest drm subsystem: GETPLANERESOURCES, GETPLANE, and SETPLANE. Planes and sprites support are ones of the latest additions to the core drm subsystem, and in my opinion they certainly are among the most interesting items there. I believe that more and more applications will be using them at some point (like the 1st one mentioned in this post – yes, the one which starts with ‘W‘), which is great.

Updates from the Intel Linux Graphics land

devel, english, intel, kernel, mesa, Uncategorized, x.org No Responses »

Jan 292012

The real life and work issues had eaten most of my time for the past 2 weeks, but things seem to be geting back to normal now. So time for semi-regular updates from the Intel Linux Graphics land.

Starting with kernel, many notable changes happened in the past weeks. To make our -next merge window process go faster, a new process was adopted for the kernel patch and branch handling process. Let me elaborate a bit more about how this is going to work.

For the past months, we had the drm-intel-next branch (containing patches intended to go into the next merge window – e.g., when the 3.3 kernel is being developed, this is the branch which contains patches intended to be included in the 3.4 kernel version), and also drm-intel-fixes branch (containing patches for the currently developed kernel – e.g., patches which fix issues which were added during the past merge window. So for instance, those are the patches which go into 3.3-rcN kernel versions after the merge window). Both of those patches were maintained by Keith Packard.

However, the amount of patches combined with other tasks resulted in a somewhat slower patch queuing process. So Daniel Vetter has volunteered himself to maintain the drm-intel-next branch from now on, reviewing, queuing and managing the patches intended to get into the next kernel merge window (for now, those are targeting the 3.4 kernel version).

At the same time, Keith Packard will continue to maintain the drm-intel-fixes branch, managing and carrying stability patches for the current kernel.

And finally, to improve the testing and availability of newer features for older kernel versions, I’ve started my own drm-intel-backports set of branches, for 3.0, 3.1 and 3.2 kernel versions – containing all the latest and greatest patches from the latest kernel releases. Of course, those patches do not follow the usual kernel stable development model, so they introduce new features, capabilities and possible issues. But for the brave souls out there willing to see and test the absolutely latest development in our drivers on top of their kernels, it should be a great chance to do so.

(I assume that I was not that fast with the drm-intel-backports patch merging process in the past 2 weeks, so for now it only contains patches from the 3.2 kernel branch. I intend to backport the 3.3 and 3.4-next patches for all those versions in the coming days. Also, apparently those backported patches do not work correctly with pre-Ironlake chipsets on 3.0 kernel, and there are some display-related issues on top of 3.1 one – I’ll look into it as well. Sorry for the delay – but the real life interfered with my patching capability for the past weeks…)

Besides those changes, we had a large number of notable kernel advances in the past weeks:

One of the most interesting features is the support for interlaced modes in the Intel Linux Graphics cards. A great work by Peter Ross, Daniel Vetter and Paulo Zanoni resulted in a series of patches which provided support for interlaced modes. These patches will be queued for inclusion in the 3.4 kernel – but when I’ll get back to my -backports series of patches, I’ll certainly include them into the 3.[012] series as well.
More Ivy bridge 3-display pipes issues were fixed, such as the hibernation problem with 3rd pipe being active.
Stabilizing the almost-ready-to-launch Ivy bridge platform, the hopefully final forcewake-related fixes were included in both drm-intel-next and drm-intel-fixes branches, and were also cherry-picked by Greg to be included in the stable 3.2 kernel as well. This should solve the remaining missing interrupts problems we were experiencing.
Initial patches to support the hardware context switching were sent by Ben Widawsky, and are accessible in his own freedesktop.org repository for testing. Hardware-supported context switching allows to save the hardware registers and state for each process, so it could essentially help the GL_EXT_transform_feedback extension and advanced geometry shading state passing between different stages. And, of course, it can also improve the stability – hardware would ensure that different processes would not interfere with each other in a harmful way.
And almost a hundred pending patches were picked by Daniel Vetter for his new drm-intel-next branch. The next merge window certainly looks interesting for the Intel Linux Graphics support in this sense…

On Mesa side, the 8.0 release is getting really close. After the 8.0-rc1 release a couple of weeks ago, lots of patches were picked into the 8.0 branch, improving the stability, performance, and fixing many rendering issues – especially on the Ivy Bridge platform. More excitingly, the communication between Mesa and Unigine developers resulted in better support for open-source drivers in the just released Oil Rush game. It is really great to see such cooperation – and Unigine-based game certainly is one of the most advanced graphical releases of past years on Linux.

Speaking about the Mesa development, this final stabilization phase prior to the 8.0 release is a great chance for you to report issues, bugs and problems before the release which is expected in a few days from now. So if you observe any last-minute problems and regressions with Mesa 8.0 branch – please, let us know! This next release looks really impressive from the technical side, but your help in additional testing is more than welcome.

On Wayland side, lots of different patches and features were received in the past weeks. Wayland and Weston development goes on with great pace – and the ones of you to attend FOSDEM next week will have some really interesting stuff to gaze upon. But I won’t spoil the surprise .

On Xserver development, the 1.12 RC2 and 1.11.4 releases were unleashed last week, together with a new glproto, util-macros and xkeyboard-config versions. The development continues non-stop, with hundreds of patches and discussions happening in the mailing lists.

And finally, the phoronix feedback I got from you over the past weeks was amazing. Thank you all for all your questions and suggestions – it was really nice to hear what you have in mind, what you like (and dislike) in our drivers and what direction we should be heading. I’ll try to answer the last remaining questions in the next few day, and will summarize everything on a dedicated blog post.

Phoronix survey about Intel Linux Graphics

devel, english, intel 7 Responses »

Jan 142012

For the ones of you who haven’t read Phoronix lately – Michael is running a survey about Intel Linux Graphics drivers for the past few days.

So far it got 10 pages of amazingly interesting comments (which I was trying to answer as time and my fingertips permitted). 95 comments as of now to be fair (sorry, 96 already – my bad ). Make sure to check it out.

In the end, I’ll try to summarize all my replies in the thread here. But it will be a long read by the looks of it.

Bleeding edge i915 for stable kernels

devel, english, intel, kernel, linux 2 Responses »

Jan 112012

One of the most frequent ~~complains~~ questions related to the Intel Linux Graphics drivers I’ve received in the past few months was: “Why Intel devs work only on the most bleeding edge, and do not give enough attention the us stable users”?

Yes, this question affects all the components of the stack – kernel, mesa, libdrm, 2D driver, and so on, but the answer to this is quite simple – this is how software gets developed. New features go into new releases, and stable releases receive bugfixes and stability improvements at most. And this is not much of an issue to the userspace components anyway – with all the LD_LIBRARY_PATH flexibility it is possible to have multiple versions of the libraries installed without any issue. But as for the kernel, indeed, it is not that easy. So most of the times, those questions were directed at the kernel part of our driver – namely, the tiny i915.ko module which is responsible for making the graphical heart of Intel-based GPU beat.

Even for the kernel, this is not exactly true – Greg’s stable trees do include most of the critical fixes for our drivers since always. But it is true to some point – most of the newest development and patching happens within the usual Linux development window – and those patches and features are then merged to the release candidates of a future kernel during the merge window. And for the kernel, it is not that easy to have multiple kernels around at the same time without having to reboot between them here and again.

So therefore, I thought on giving a small gift to the users who are not still ready to jump into the latest and greatest kernels releases – but still want to enjoy the goodies brought with the latest versions of the graphics driver. So I prepared two kernel branches on my freedesktop.org kernel repository:

3.0-drm-intel-backports — latest 3.0.x kernel with all the i915 patches from latest kernel release. Right now, it is 3.0.16 + 195 backported patches. Diffstat reports 78 files changed, 4988 insertions(+), 2176 deletions(-).
3.1-drm-intel-backports — latest 3.1.x kernel with all the i915 patches from latest kernel release. Right now, it is 3.1.8 + 104 backported patches. Diffstat reports 74 files changed, 3147 insertions(+), 1589 deletions(-).

Besides driver backports, the patches which affect multiple drivers (like, i915, nouveau and r128) were also backported in full in those branches. And all the required build and API dependencies (like HDMI/DP ELD or drm/gem API changes) are also included in full.

I’ll try to keep those branches maintained on a semi-periodic basis and synchronized with the latest updates both from -stable branches, and from newest kernel releases.

Of course, let me put an obligatory support and stability statement:

Those branches are not supported officially, are experimental and can be unstable or even broken sometimes (in which case, if you’d be kind enough to let me know about that, I’d try to fix them ASAP). So use them at your own risk.

Other than that, have fun .