[REGRESSION] drm/amd/display: Radeon 840M/860M: bisected suspend crash

[ggo@tuxedocomputers.com]

Hi,

I have discovered that two small form factor desktops with Ryzen AI 7
350 and Ryzen AI 5 340 crash when woken up from suspend. I can see how
the LED on the USB mouse is switched on when I trigger a resume via
keyboard button, but the display remains black. The kernel also no
longer responds to Magic SysRq keys in this state.

The problem affects all kernels after merge b50753547453 (v6.11.0). But
this merge only adds PCI_DEVICE_ID_AMD_1AH_M60H_ROOT with commit
59c34008d (necessary to trigger this bug with Ryzen AI CPU).
I cherry-picked this commit and continued searching. Which finally led
me to commit f6098641d3e - drm/amd/display: fix s2idle entry for DCN3.5+

If I remove the code, which has changed somewhat in the meantime, then
the suspend works without any problems. See the following patch.

Regards,
Georg


diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index d3100f641ac6..76204ae70acc 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -3121,9 +3121,6 @@ static int dm_suspend(struct amdgpu_ip_block
*ip_block)

 	dc_set_power_state(dm->dc, DC_ACPI_CM_POWER_STATE_D3);

-	if (dm->dc->caps.ips_support && adev->in_s0ix)
-		dc_allow_idle_optimizations(dm->dc, true);
-
 	dc_dmub_srv_set_power_state(dm->dc->ctx->dmub_srv,
DC_ACPI_CM_POWER_STATE_D3);

 	return 0;