Re: [PATCH] drm/i915: Fix legacy gamma lut updates in Linux 4.7-rc6

[Mario Kleiner]

On 07/12/2016 12:50 PM, Lionel Landwerlin wrote:
> Hi Mario,

Hi Lionel,

> There was a couple of patch to fix this issue :
>
> https://patchwork.freedesktop.org/series/5467/
> https://patchwork.freedesktop.org/series/5466/

Looking at them they should fix the issue, but they seem to be stuck in 
review?

> I tested this late last week on drm-intel-nightly, it seems a series of
> revert fixed most of the issues.

You mean something else has fixed legacy gamma updates, as i can't find 
above patches applied on drm-intel-nightly?

Are those fixes supposed to be already part of 4.7-rc7, the final rc afaik?

thanks,
-mario


> Cheers,
>
> -
> Lionel
>
> On 12/07/16 11:33, Mario Kleiner wrote:
> > Updating legacy gamma tables, e.g., via RandR doesn't work at all
> > as of Linux 4.7-rc6.
> >
> > Reason seems to be that the required call to
> > drm_atomic_helper_commit_planes_on_crtc is skipped in
> > intel_atomic_commit after userspace set new gamma tables,
> > because neither crtc->state->planes_changed nor
> > update_pipe (= pipe_config->update_pipe) are true.
> >
> > Removing the check for planes_changed || update_pipe fixes
> > gamma table updates.
> >
> > The code for Linux 4.8 drm-next has changed a lot in that area
> > wrt. 4.7, but the new code for 4.8 also removed those checks
> > and calls drm_atomic_helper_commit_planes_on_crtc unconditionally,
> > and legacy gamma lut updates work on drm-next, so this seems to be
> > the right solution.
> >
> > Tested also shutdown/reboot, suspend/resume, (un-)plugging displays,
> > mode switches for resolution/refresh rate, display rotation, and
> > page-flipping/pageflip timing on Intel HD Ironlake to confirm the
> > fix apparently doesn't break anything under X11.
> >
> > Signed-off-by: Mario Kleiner <mario.kleiner.de@xxxxxxxxx>
> > Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
> > Cc: Lionel Landwerlin <lionel.g.landwerlin@xxxxxxxxx>
> > Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
> > ---
> >   drivers/gpu/drm/i915/intel_display.c | 4 +---
> >   1 file changed, 1 insertion(+), 3 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_display.c
> > b/drivers/gpu/drm/i915/intel_display.c
> > index 04452cf..eb8fb36 100644
> > --- a/drivers/gpu/drm/i915/intel_display.c
> > +++ b/drivers/gpu/drm/i915/intel_display.c
> > @@ -13685,7 +13685,6 @@ static int intel_atomic_commit(struct
> > drm_device *dev,
> >           bool modeset = needs_modeset(crtc->state);
> >           struct intel_crtc_state *pipe_config =
> >               to_intel_crtc_state(crtc->state);
> > -        bool update_pipe = !modeset && pipe_config->update_pipe;
> >           if (modeset && crtc->state->active) {
> >               update_scanline_offset(to_intel_crtc(crtc));
> > @@ -13699,8 +13698,7 @@ static int intel_atomic_commit(struct
> > drm_device *dev,
> >               drm_atomic_get_existing_plane_state(state, crtc->primary))
> >               intel_fbc_enable(intel_crtc);
> > -        if (crtc->state->active &&
> > -            (crtc->state->planes_changed || update_pipe))
> > +        if (crtc->state->active)
> >               drm_atomic_helper_commit_planes_on_crtc(old_crtc_state);
> >           if (pipe_config->base.active && needs_vblank_wait(pipe_config))