This bug is awaiting verification that the linux-nvidia- tegra/6.8.0-1001.1 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-noble-linux-nvidia-tegra' to 'verification-done-noble-linux-nvidia-tegra'. If the problem still exists, change the tag 'verification-needed-noble-linux-nvidia-tegra' to 'verification-failed-noble-linux-nvidia-tegra'.
If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you! ** Tags added: kernel-spammed-noble-linux-nvidia-tegra-v2 verification-needed-noble-linux-nvidia-tegra -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/2072755 Title: i915: Fixup regressions introduced with enabling single CCS engine Status in linux package in Ubuntu: Fix Released Status in linux source package in Noble: Fix Released Bug description: BugLink: https://bugs.launchpad.net/bugs/2072755 [Impact] Recently, the Intel i915 susbsystem underwent a change that limited the number of CCS engines that were initialised by default, and exposed to the user. Different chipsets have differing amounts of CCS engines, but most available in the market have 4 CCS engines. The new change just starts a single engine only, and allocates all CCS slices to this single engine. This single engine is then exposed to userspace. This effort is to workaround a hardware bug. This all happened in: commit 6db31251bb265813994bfb104eb4b4d0f44d64fb Author: Andi Shyti <andi.sh...@linux.intel.com> Date: Thu Mar 28 08:34:05 2024 +0100 Subject: drm/i915/gt: Enable only one CCS for compute workload Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6db31251bb265813994bfb104eb4b4d0f44d64fb which landed in: $ git describe --contains 67f164e8510b16bda18642464863dba87a33d8cb Ubuntu-6.8.0-38.38~525 There have been some side effects as a result of these changes, leading to failure of userspace applications, namely in video transcoding with ffmepg, resulting in fence expiration errors in dmesg like: [ 81.026591] Fence expiration time out i915-0000:01:00.0:ffmpeg[521]:2! There has also been a performance impact introduced by this change, which dropped performance of the GPU to 1/4 of what it was previously. This is likely due to most ARC GPUs usually having 4 CCS engines, and going down to 1 only without actually allocating the other three. There are no workarounds. Users are suggested to downgrade to 6.8.0-36-generic while the fix is coming. [Fix] The regression was fixed by these two commits: commit aee54e282002a127612b71255bbe879ec0103afd Author: Andi Shyti <andi.sh...@linux.intel.com> Date: Fri Apr 26 02:07:23 2024 +0200 Subject: drm/i915/gt: Automate CCS Mode setting during engine resets Link: https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/noble/commit/?id=aee54e282002a127612b71255bbe879ec0103afd commit ee01b6a386eaf9984b58a2476e8f531149679da9 Author: Andi Shyti <andi.sh...@linux.intel.com> Date: Fri May 17 11:06:16 2024 +0200 Subject: drm/i915/gt: Fix CCS id's calculation for CCS mode setting Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ee01b6a386eaf9984b58a2476e8f531149679da9 "drm/i915/gt: Automate CCS Mode setting during engine resets" is already applied to noble/master-next through upstream stable v6.8.10. We just need "drm/i915/gt: Fix CCS id's calculation for CCS mode setting". It is queued up for v6.9.4, but that could still be another SRU cycle or two away. So send it now. "drm/i915/gt: Fix CCS id's calculation for CCS mode setting" restores another 1/4 performance, but some performance issues still remain, and will hopefully be addressed in a future patch. [Testcase] This affects video transcoding with ffmpeg, on machines equipped with Intel ARC GPUs. An example ffmpeg command might be: /usr/lib/jellyfin-ffmpeg/ffmpeg -analyzeduration 200M -probesize 1G -ss 00:00:03.000 -noaccurate_seek -init_hw_device vaapi=va:,kernel_driver=i915,driver=iHD -init_hw_device qsv=qs@va -filter_hw_device qs -hwaccel vaapi -hwaccel_output_format vaapi -noautorotate -i file:"/path/to/1080_video.mkv" -noautoscale -map_metadata -1 -map_chapters -1 -threads 0 -map 0:0 -map 0:1 -map -0:s -codec:v:0 av1_qsv -preset veryfast -b:v 3616000 -maxrate 3616000 -bufsize 7232000 -g:v:0 72 -keyint_min:v:0 72 -vf "setparams=color_primaries=bt709:color_trc=bt709:colorspace=bt709,scale_vaapi=w=1280:h=720:format=nv12:extra_hw_frames=24,hwmap=derive_device=qsv,format=qsv" -codec:a:0 libfdk_aac -ac 2 -vbr:a 5 -copyts -avoid_negative_ts disabled -max_muxing_queue_size 2048 -f hls -max_delay 5000000 -hls_time 3 -hls_segment_type fmp4 -hls_fmp4_init_filename "c30716eb121448346fcc00a2440071a3-1.mp4" -start_number 1 -hls_segment_filename "/var/lib/jellyfin/transcodes/c30716eb121448346fcc00a2440071a3%d.mp4" -hls_playlist_type vod -hls_list_size 0 -y "/var/lib/jellyfin/transcodes/c30716eb121448346fcc00a2440071a3.m3u8 Another user on bug 2072933 came up with this minimalist reproducer: #include <cstdio> #include <sycl/sycl.hpp> int main() { // auto selector = sycl::cpu_selector_v; // Works fine auto selector = sycl::gpu_selector_v; auto queue = sycl::queue(selector); printf("Hello\n"); queue.submit([&](sycl::handler &cgh) { cgh.parallel_for(sycl::range(1), [=](sycl::item<1> item) {}); }); queue.wait(); printf("Bye\n"); return 0; } $ icpx -fsycl sycltest.cpp -o sycltest $ ./sycltest These commands should run successfully to completion. On failure, they will emit in dmesg: [ 81.026591] Fence expiration time out i915-0000:01:00.0:ffmpeg[521]:2! A test kernel is available in the following ppa: https://launchpad.net/~mruffell/+archive/ubuntu/lp2072755-test If you install the test kernel, things should work correctly. [Where problems could occur] This issue affects users of i915, which is a pretty universal integrated GPU present on Intel processors. While these patches are unlikely to cause outages that stop the primary display from functioning, any further regressions may add additional performance impact or prevent workloads from executing correctly. These patches are all accepted into upstream -stable, and we would consume them in due course anyway. If a regression were to occur, there are no workarounds, and users would need to select an older kernel until a fix is available. [Other info] Upstream Bug: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/10895 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2072755/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
