Re: [PATCH v4 3/5] drm: add SimpleDRM driver

[Daniel Vetter]

On Fri, Sep 2, 2016 at 1:48 AM, David Herrmann <dh.herrmann@xxxxxxxxx> wrote:
> So either the drm_simple_kms_helpers are buggy, or the SimpleDRM use
> of it. On DPMS updates, I get:
>
> Sep 02 01:00:39 david-t2 kernel:
> [drm:drm_atomic_helper_commit_cleanup_done [drm_kms_helper]] *ERROR*
> [CRTC:25:crtc-0] flip_done timed out
> Sep 02 01:00:39 david-t2 kernel: ------------[ cut here ]------------
> Sep 02 01:00:39 david-t2 kernel: WARNING: CPU: 3 PID: 352 at
> drivers/gpu/drm/drm_atomic_helper.c:1549
> drm_atomic_helper_commit_hw_done+0xab/0xb0 [drm_kms_helper]
>
> The atomic-commit originates in:
> drm_atomic_helper_connector_dpms()
>
> Any idea what is missing there? I haven't looked much into the
> atomic-helpers, yet.

The bugfix for that is in latest drm-misc (or well, should be at
least). And you need to make sure to call drm_crtc_send_vblank_event
(if there's an event) from your update hook. That /should/ work, but I
didn't test it myself. flip_done not happening is when the
driver/helpers fail to submit the event for some reason or another.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch