On 2019-05-30 3:51 p.m., Nicholas Kazlauskas wrote: > [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. > > Cc: Roman Li <[email protected]> > Cc: Leo Li <[email protected]> > Cc: Harry Wentland <[email protected]> > Signed-off-by: Nicholas Kazlauskas <[email protected]>
Reviewed-by: Harry Wentland <[email protected]> Harry > --- > 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 57359037ed7c..796f83ca7a4c 100644 > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c > +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c > @@ -6248,7 +6248,17 @@ 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", > _______________________________________________ amd-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/amd-gfx
