A hotplug bug in AMDGPU

[Mikulas Patocka]

Hi

There's a bug with monitor hotplug starting with the kernel 5.7.

I have Radeon RX 570. If I boot the system with the monitor unplugged and 
then plug the monitor via DVI, the kernel 5.6 and below will properly 
initialized graphics; the kernels 5.7+ will not initialize it - and the 
monitor reports no signal.

I bisected the issue and it is caused by the patch 
4fdda2e66de0b7d37aa27af3c1bbe25ecb2d5408 ("drm/amdgpu/runpm: enable runpm 
on baco capable VI+ asics")

When I remove the code that sets adev->runpm on the kernel 5.12, monitor 
hotplug works correctly.

Mikulas


Signed-off-by: Mikulas Patocka <mpatocka at redhat.com>

---
 drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c |    2 --
 1 file changed, 2 deletions(-)

Index: linux-5.12/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
===================================================================
--- linux-5.12.orig/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c	2021-04-26 14:50:53.000000000 +0200
+++ linux-5.12/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c	2021-05-03 16:19:54.000000000 +0200
@@ -183,8 +183,6 @@ int amdgpu_driver_load_kms(struct amdgpu
 				adev->runpm = true;
 			break;
 		default:
-			/* enable runpm on CI+ */
-			adev->runpm = true;
 			break;
 		}
 		if (adev->runpm)