From 50d40cd6913db43ae740da1d411b86439061a226 Mon Sep 17 00:00:00 2001 From: Nicholas Kazlauskas Date: Thu, 30 May 2019 15:51:14 -0400 Subject: [PATCH 2046/2940] drm/amd/display: Don't set mode_changed=false if the stream was removed [Why] When switching from vt to desktop with EDID emulation we can receive an atomic commit such that we have a crtc where mode_changed = true. During the dm_update_crtc_state disable pass we remove the stream from the context and free it on the dm_new_crtc_state. During the enable pass we compare the new provisional stream to the dm_old_crtc_state->stream and determine that the stream is unchanged and no scaling has been changed. Following this, new_crtc_state->mode_changed is then set to false. The connectors haven't changed and the CRTC active state hasn't changed so drm_atomic_crtc_needs_modeset returns false, so we jump to skip_modeset and we hit: BUG_ON(dm_new_crtc_state->stream == NULL); ...since the old stream is gone from the context and the new stream is also still NULL. [How] Ensure that we still a stream to reuse before checking if we can reuse the old stream without a full modeset. Signed-off-by: Nicholas Kazlauskas Reviewed-by: Harry Wentland Signed-off-by: Chaudhary Amit Kumar --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) 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 e089e384b0ba..ad2eb220ff90 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -6295,7 +6295,17 @@ static int dm_update_crtc_state(struct amdgpu_display_manager *dm, } dm_new_crtc_state->abm_level = dm_new_conn_state->abm_level; - if (dc_is_stream_unchanged(new_stream, dm_old_crtc_state->stream) && + /* + * If we already removed the old stream from the context + * (and set the new stream to NULL) then we can't reuse + * the old stream even if the stream and scaling are unchanged. + * We'll hit the BUG_ON and black screen. + * + * TODO: Refactor this function to allow this check to work + * in all conditions. + */ + if (dm_new_crtc_state->stream && + dc_is_stream_unchanged(new_stream, dm_old_crtc_state->stream) && dc_is_stream_scaling_unchanged(new_stream, dm_old_crtc_state->stream)) { new_crtc_state->mode_changed = false; DRM_DEBUG_DRIVER("Mode change not required, setting mode_changed to %d", -- 2.17.1