https://bugs.freedesktop.org/show_bug.cgi?id=107607
--- Comment #1 from Paul Menzel pmenzel+bugs.freedesktop@molgen.mpg.de --- Created attachment 141201 --> https://bugs.freedesktop.org/attachment.cgi?id=141201&action=edit Linux 4.18+ messages with drm.debug=0xe
Here is a verbose log. I believe it’s related to DP 1.2 and the MST Dell monitor.
[ 15.113453] [drm:generic_reg_wait [amdgpu]] REG_WAIT taking a while: 24ms in enc1_stream_encoder_dp_blank line:804 [ 15.146724] [drm:generic_reg_wait [amdgpu]] REG_WAIT taking a while: 3ms in optc1_disable_crtc line:513 [ 23.953593] [drm:generic_reg_wait [amdgpu]] REG_WAIT taking a while: 5ms in mpc1_assert_idle_mpcc line:103 [ 24.003514] [drm:generic_reg_wait [amdgpu]] REG_WAIT taking a while: 7ms in mpc1_assert_idle_mpcc line:103 [ 100.425097] [drm:generic_reg_wait [amdgpu]] REG_WAIT taking a while: 6ms in mpc1_assert_idle_mpcc line:103 [ 100.441735] [drm:generic_reg_wait [amdgpu]] REG_WAIT taking a while: 7ms in mpc1_assert_idle_mpcc line:103 [ 104.509792] [drm:generic_reg_wait [amdgpu]] *ERROR* REG_WAIT timeout 10us * 3000 tries - enc1_stream_encoder_dp_blank line:804 [ 104.509841] WARNING: CPU: 1 PID: 1550 at drivers/gpu/drm/amd/amdgpu/../display/dc/dc_helper.c:254 generic_reg_wait+0xe7/0x160 [amdgpu] [ 104.509895] RIP: 0010:generic_reg_wait+0xe7/0x160 [amdgpu] [ 104.517863] [drm:generic_reg_wait [amdgpu]] REG_WAIT taking a while: 2ms in optc1_disable_crtc line:513 [ 108.605859] [drm:generic_reg_wait [amdgpu]] *ERROR* REG_WAIT timeout 10us * 3000 tries - enc1_stream_encoder_dp_blank line:804 [ 108.605909] WARNING: CPU: 2 PID: 1550 at drivers/gpu/drm/amd/amdgpu/../display/dc/dc_helper.c:254 generic_reg_wait+0xe7/0x160 [amdgpu] [ 108.605964] RIP: 0010:generic_reg_wait+0xe7/0x160 [amdgpu] [ 108.610990] [drm:generic_reg_wait [amdgpu]] REG_WAIT taking a while: 1ms in optc1_disable_crtc line:513 [ 110.529644] [drm:generic_reg_wait [amdgpu]] REG_WAIT taking a while: 3ms in optc1_wait_for_state line:782 [ 110.536052] [drm:generic_reg_wait [amdgpu]] REG_WAIT taking a while: 2ms in optc1_wait_for_state line:782 [ 115.561370] [drm:generic_reg_wait [amdgpu]] REG_WAIT taking a while: 2ms in mpc1_assert_idle_mpcc line:103 [ 115.578008] [drm:generic_reg_wait [amdgpu]] REG_WAIT taking a while: 5ms in mpc1_assert_idle_mpcc line:103 [ 115.686970] [drm:generic_reg_wait [amdgpu]] *ERROR* REG_WAIT timeout 10us * 3000 tries - enc1_stream_encoder_dp_blank line:804 [ 115.687021] WARNING: CPU: 3 PID: 48 at drivers/gpu/drm/amd/amdgpu/../display/dc/dc_helper.c:254 generic_reg_wait+0xe7/0x160 [amdgpu] [ 115.687079] RIP: 0010:generic_reg_wait+0xe7/0x160 [amdgpu] [ 115.694125] [drm:generic_reg_wait [amdgpu]] REG_WAIT taking a while: 2ms in optc1_disable_crtc line:513 [ 115.737576] [drm:generic_reg_wait [amdgpu]] *ERROR* REG_WAIT timeout 10us * 3000 tries - enc1_stream_encoder_dp_blank line:804 [ 115.737626] WARNING: CPU: 3 PID: 48 at drivers/gpu/drm/amd/amdgpu/../display/dc/dc_helper.c:254 generic_reg_wait+0xe7/0x160 [amdgpu] [ 115.737678] RIP: 0010:generic_reg_wait+0xe7/0x160 [amdgpu] [ 115.744042] [drm:generic_reg_wait [amdgpu]] REG_WAIT taking a while: 1ms in optc1_disable_crtc line:513 [ 116.250536] [drm:generic_reg_wait [amdgpu]] REG_WAIT taking a while: 1ms in optc1_wait_for_state line:782 [ 116.267508] [drm:generic_reg_wait [amdgpu]] REG_WAIT taking a while: 5ms in mpc1_assert_idle_mpcc line:103 [ 256.781411] [drm:generic_reg_wait [amdgpu]] REG_WAIT taking a while: 5ms in mpc1_assert_idle_mpcc line:103 [ 256.798049] [drm:generic_reg_wait [amdgpu]] REG_WAIT taking a while: 7ms in mpc1_assert_idle_mpcc line:103 [ 256.830971] [drm:generic_reg_wait [amdgpu]] REG_WAIT taking a while: 3ms in optc1_disable_crtc line:513 [ 256.864242] [drm:generic_reg_wait [amdgpu]] REG_WAIT taking a while: 5ms in optc1_disable_crtc line:513 [ 260.684885] [drm:generic_reg_wait [amdgpu]] REG_WAIT taking a while: 2ms in optc1_wait_for_state line:782 [ 260.701867] [drm:generic_reg_wait [amdgpu]] REG_WAIT taking a while: 6ms in mpc1_assert_idle_mpcc line:103