Hello, (Apologies if I have CC'd the wrong people/places - I just went by what get_maintainer.pl -f drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c said) I recently upgraded from Ubuntu 20.04 (5.15.0-119.129~20.04.1-generic kernel) to Ubuntu 24.04 (6.8.0-44-generic kernel) and found that while booting the kernel hangs for around 15 seconds just before the amdgpu driver is loaded: [ 4.459519] radeon 0000:01:05.0: [drm] Cannot find any crtc or sizes [ 4.460118] probe of 0000:01:05.0 returned 0 after 902266 usecs [ 4.460184] initcall radeon_module_init+0x0/0xff0 [radeon] returned 0 after 902473 usecs [ 4.465797] calling drm_buddy_module_init+0x0/0xff0 [drm_buddy] @ 122 [ 4.465853] initcall drm_buddy_module_init+0x0/0xff0 [drm_buddy] returned 0 after 29 usecs [ 4.469419] radeon 0000:01:05.0: [drm] Cannot find any crtc or sizes [ 4.473831] calling drm_sched_fence_slab_init+0x0/0xff0 [gpu_sched] @ 122 [ 4.473892] initcall drm_sched_fence_slab_init+0x0/0xff0 [gpu_sched] returned 0 after 31 usecs [ 18.724442] calling amdgpu_init+0x0/0xff0 [amdgpu] @ 122 [ 18.726303] [drm] amdgpu kernel modesetting enabled. [ 18.726576] amdgpu: Virtual CRAT table created for CPU [ 18.726609] amdgpu: Topology: Add CPU node [ 18.726787] initcall amdgpu_init+0x0/0xff0 [amdgpu] returned 0 after 528 usecs I've checked and the problem still exists in 6.11.0-061100rc7-generic (which is close to vanilla upstream). The graphics card I have is: 01:05.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] RS880M [Mobility Radeon HD 4225/4250] (prog-if 00 [VGA controller]) 01:05.0 0300: 1002:9712 (prog-if 00 [VGA controller]) Subsystem: 103c:1609 At first I thought the problem was related to the change https://github.com/torvalds/linux/commit/eb4fd29afd4aa1c98d882800ceeee7d1f5262803 ("drm/amdgpu: bind to any 0x1002 PCI diplay [sic] class device") which now means my card is claimed by two drivers (radeon and amdgpu). That change complicated things because: - The amdgpu module and its dependencies remain permanently present (which never used to happen) - It took some time for me to realise that the amdgpu driver hadn't suddenly grown the ability to support this old card :-) There is a nice table on https://www.x.org/wiki/RadeonFeature/#decoderringforengineeringvsmarketingnames that shows it is part of the R600 family and https://www.x.org/wiki/RadeonFeature/#featurematrixforfreeradeondrivers shows that R600 is only supported by the radeon driver. However, testing a 5.16.20-051620-generic kernel showed that while the amdgpu module is loaded, there is no 15 second hang... So far my testing has the following results: - 5.16.20-051620-generic - amdgpu loaded, no hang - 5.18.19-051819-generic - amdgpu loaded, no hang - 6.0.0-060000-generic - amdgpu loaded, hang - 6.2.0-060200-generic - amdgpu loaded, hang - 6.8.0-44-generic - amdgpu loaded, hang - 6.11.0-061100rc7-generic - amdgpu loaded, hang To work around the problem I've taken to blacklisting amdgpu in /etc/modprobe.d/ which makes the hang disappear. Does anyone else see this issue? Is there something better than my current workaround? What do other drivers that want to bind to such a large set of devices do? Further, while I'm already using initcall_debug, is there any other kernel boot parameter to make what's happening more visible? -- Sitsofe
