Software Engineering Radio is a podcast for people in IT/development with over 700 episodes across many topics over 20 years. They haven't touched on the Linux kernel much. I was invited on as part of my role at Red Hat as a Distinguished Engineer, but the podcast is really an insight into kernel maintenance, in graphics and beyond, touching on the scope and scale of the project. It was my first…
I'm doing a podcast recording this week, so I wanted to run some numbers so I could have some facts rather than feels. It turns out my feels were off by a factor of 3 or so. If asked, I've always said the contributor count to the drm subsystem is probably in the 100 or so developers per release cycle. Did the simplest: git log --format='%aN' v6.14..v6.15 drivers/gpu/drm/ include/uapi/drm/…
This topic came up at kernel maintainers summit and some other groups have been playing around with it, particularly the BPF folks, and Chris Mason's work on kernel review prompts[1] for regressions. Red Hat have asked engineers to investigate some workflow enhancements with AI tooling, so I decided to let the vibecoding off the leash. My main goal: - Provide AI led patch review for drm patches -…
Just to keep up some blogging content, I'll do where did I spend/waste time last couple of weeks. I was working on two nouveau kernel bugs in parallel (in between whatever else I was doing). Bug 1: Lyude, 2 or 3 weeks ago identified the RTX6000 Ada GPU wasn't resuming from suspend. I plugged in my one and indeed it wasn't. Turned out since we moved to 570 firmware, this has been broken. We started…
F43 picked up the two patches I created to fix a bunch of deadlocks on laptops reported in my previous blog posting. Turns out Vulkan layers have a subtle thing I missed, and I removed a line from the device select layer that would only matter if you have another layer, which happens under steam. The fedora update process caught this, but it still got published which was a mistake, need to…
I had a bug appear in my email recently which led me down a rabbit hole, and I'm going to share it for future people wondering why we can't have nice things. Bug: 1. Get an intel/nvidia (newer than Turing) laptop. 2. Log in to GNOME on Fedora 42/43 3. Hotplug a HDMI port that is connected to the NVIDIA GPU. 4. Desktop stops working. My initial reproduction got me a hung mutter process with a nice…
AMD have announced the end of the AMDVLK open driver in favour of focusing on radv for Linux use cases. When Bas and I started radv in 2016, AMD were promising their own Linux vulkan driver, which arrived in Dec 2017. At this point radv was already shipping in most Linux distros. AMD strategy of having AMDVLK was developed via over the wall open source releases from internal closed development was…
One of my pet peeves around running local LLMs and inferencing is the sheer mountain of shit^W^W^W complexity of compute stacks needed to run any of this stuff in an mostly optimal way on a piece of hardware. CUDA, ROCm, and Intel oneAPI all to my mind scream over-engineering on a massive scale at least for a single task like inferencing. The combination of closed source, over the wall open…
Blog posts are like buses sometimes... I've spent time over the last month enabling Blackwell support on NVK, the Mesa vulkan driver for NVIDIA GPUs. Faith from Collabora, the NVK maintainer has cleaned up and merged all the major pieces of this work and landed them into mesa this week. Mesa 25.2 should ship with a functioning NVK on blackwell. The code currently in mesa main passes all tests in…
I should have mentioned this here a week ago. The Vulkan AV1 encode extension has been out for a while, and I'd done the initial work on enabling it with radv on AMD GPUs. I then left it in a branch, which Benjamin from AMD picked up and fixed a bunch of bugs, and then we both got distracted. I realised when doing VP9 that it hasn't landed, so did a bit of cleanup. Then David from AMD picked it up…
The Vulkan WG has released VK_KHR_video_decode_vp9. I did initial work on a Mesa extensions for this a good while back, and I've updated the radv code with help from AMD and Igalia to the final specification. There is an open MR[1] for radv to add support for vp9 decoding on navi10+ with the latest firmware images in linux-firmware. It is currently passing all VK-GL-CTS tests for VP9 decode.…
There's been a couple of mentions of Rust4Linux in the past week or two, one from Linus on the speed of engagement and one about Wedson departing the project due to non-technical concerns. This got me thinking about project phases and developer types. Archetypes: I will regret making an analogy, in an area I have no experience in, but let's give it a go with a road building analogy. Let's sort…
Vulkan Video AV1 decode has been released, and I had some partly working support on Intel ANV driver previously, but I let it lapse. The branch is currently [1]. It builds, but is totally untested, I'll get some time next week to plug in my DG2 and see if I can persuade it to decode some frames. Update: the current branch decodes one frame properly, reference frames need more work unfortunately.…
The Khronos Group announced VK_KHR_video_decode_av1 [1], this extension adds AV1 decoding to the Vulkan specification. There is a radv branch [2] and merge request [3]. I did some AV1 work on this in the past, but I need to take some time to see if it has made any progress since. I'll post an ANV update once I figure that out. This extension is one of the ones I've been wanting for a long time,…
Vulkan 1.3.274 moves the Vulkan encode work out of BETA and moves h264 and h265 into KHR extensions. radv support for the Vulkan video encode extensions has been in progress for a while. The latest branch is at [1]. This branch has been updated for the new final headers. Updated: It passes all of h265 CTS now, but it is failing one h264 test. Initial ffmpeg support is [2]. [1]…
Linus has pulled the initial GSP firmware support for nouveau. This is just the first set of work to use the new GSP firmware and there are likely many challenges and improvements ahead. To get this working you need to install the firmware which hasn't landed in linux-firmware yet. For Fedora this copr has the firmware in the necessary places:…
Sriram invited me to the oneAPI meetup, and I felt I hadn't summed up the state of compute and community development in a while. Enjoy 45 minutes of opinions! https://www.youtube.com/watch?v=HzzLY5TdnZo
The initial NVK (nouveau vulkan) experimental driver has been merged into mesa master[1], and although there's lots of work to be done before it's application ready, the main reason it was merged was because the initial kernel work needed was merged into drm-misc-next[2] and will then go to drm-next for the 6.6 merge window. (This work is separate from the GSP firmware enablement required for…
I recently came across tinygrad as a small powerful nn framework that had an OpenCL backend target and could run LLaMA model. I've been looking out for rusticl workloads, and this seemed like a good one, and I could jump on the AI train, and run an LLM in my house! I started it going on my Radeon 6700XT with the latest rusticl using radeonsi with the LLVM backend, and I could slowly interrogate a…
Thanks for all the suggestions, on here, and on twitter and on mastodon, anyway who noted I could use a single fd and avoid all the pain was correct! I hacked up an ever growing ftruncate/madvise memfd and it seemed to work fine. In order to use it for sparse I have to use it for all device memory allocations in lavapipe which means if I push forward I probably have to prove it works and scales a…
Mike nerdsniped me into wondering how hard sparse memory support would be in lavapipe. The answer is unfortunately extremely. Sparse binding essentially allows creating a vulkan buffer/image of a certain size, then plugging in chunks of memory to back it in page-size multiple chunks. This works great with GPU APIs where we've designed this, but it's actually hard to pull off on the CPU. Currently…
F38 just released and seeing a bunch of people complain that TF2 dies on AMD or other platforms when lavapipe is installed. Who's at fault? I've no real idea. How to fix it? I've no real idea. What's happening? AMD OpenGL drivers use LLVM as the backend compiler. Fedora 38 updated to LLVM 16. LLVM 16 is built with c++17 by default. C++17 introduces new "operator new/delete" interfaces[1]. TF2…
There are plans for nouveau to support using the NVIDIA supplied GSP firmware in order to support new hardware going forward The nouveau project doesn't have any input or control over the firmware. NVIDIA have made no promises around stable ABI or firmware versioning. The current status quo is that NVIDIA will release versioned signed gsp firmwares as part of their driver distribution packages…
While going over the AV1 a few people commented on the lack of VP9 and a few people said it would be an easier place to start etc. Daniel Almeida at Collabora took a first pass at writing the spec up, and I decided to go ahead and take it to a working demo level. Lynne was busy, and they'd already said it should take an afternoon, so I decided to have a go at writing the ffmpeg side for it as well…
Okay just a short status update. radv H264/H265 decode: The radv h264/h265 support has been merged to mesa main branch. It is still behind RADV_PERFTEST=video_decode flag, and should work for basics from VI/GFX8+. It still has not passed all the CTS tests. anv H264 decode: The anv h264 decode support has been merged to mesa main branch. It has been tested from Skylake up to DG2. It has no enable…