Revert "drm/amd: Keep display off while going into S4"

commit 7e7cb7a upstream.

commit 68bfdc8 ("drm/amd: Keep display off while going into S4")
attempted to keep displays off during the S4 sequence by not resuming
display IP.  This however leads to hangs because DRM clients such as the
console can try to access registers and cause a hang.

Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4155
Fixes: 68bfdc8 ("drm/amd: Keep display off while going into S4")
Reviewed-by: Alex Deucher <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mario Limonciello <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>
(cherry picked from commit e485502)
Cc: [email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: superm1

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -3315,11 +3315,6 @@ static int dm_resume(void *handle)
 
 		return 0;
 	}
-
-	/* leave display off for S4 sequence */
-	if (adev->in_s4)
-		return 0;
-
 	/* Recreate dc_state - DC invalidates it when setting power state to S3. */
 	dc_state_release(dm_state->context);
 	dm_state->context = dc_state_create(dm->dc, NULL);