Created attachment 294169 [details] dmesg from where X11 initializes Booting into mainline 5.10.1 oopses in the amdgpu module in the routine amdgpu_connector_dp_detect(). Kernels 5.9.15 and below are not affected. Full dmesg attached. Brief snippet of oops: BUG: kernel NULL pointer dereference, address: 0000000000000060 Call Trace: amdgpu_connector_dp_detect+0x159/0x320 [amdgpu] drm_helper_probe_detect+0x93/0xd0 drm_helper_probe_single_connector_modes+0x60c/0x7e0 drm_client_modeset_probe+0x25c/0x13c0 [etc] The GPU is inbuilt within the AMD A10-7870K (Radeon R7). At system start: modprobe amdgpu clk_support=1 modprobe radeon clk_support=0 Console output seems to be OK during system initialization. But as soon as Xorg starts, the oops occurs, and video output ceases. System is still responsive via the network. The oops locks the video hardware spectacularly. Neither the BIOS nor pressing the motherboard <reset> button has any effect. Only a power-cycle will get things back to normal.
Fixed with this patch: https://patchwork.freedesktop.org/patch/408230/ Which will be landing soon.
(In reply to Alex Deucher from comment #1) > Fixed with this patch: > https://patchwork.freedesktop.org/patch/408230/ > Which will be landing soon. Nevermind, this only applies when amdgpu.dc=1
Can you bisect?
OK, just finished the bisect. The errant commit is: 65bf2cf95d3ade4b56c35b17bb955a64b7f4b019 "drm/amdgpu: utilize subconnector property for DP through atombios" I reverted that out of my 5.10.1, and all is happy on my machine.
Created attachment 294203 [details] possible fix I think this patch should fix it.
(In reply to Alex Deucher from comment #5) > Created attachment 294203 [details] > possible fix > > I think this patch should fix it. Will the fix be part of 5.10.2? Thx.
Tested the patch from comment 5, and I confirm it works as intended. Thanks, Alex, for the fix! I'll mark as closed. Tested-By: Kris Karas <bugs-a17@moonlit-rail.com>
Created attachment 294349 [details] journalctl for debugging purposes