[Intel-gfx] [(resend) PATCH 1/2] drm/i915: Calculate vlv/chv intermediate watermarks correctly, v3.

[Ville Syrjälä]

On Fri, Nov 17, 2017 at 03:47:58PM +0100, Maarten Lankhorst wrote:
> Op 17-11-17 om 14:31 schreef Ville Syrjälä:
> > On Wed, Nov 15, 2017 at 05:31:56PM +0100, Maarten Lankhorst wrote:
> >> The watermarks it should calculate against are the old optimal watermarks.
> >> The currently active crtc watermarks are pure fiction, and are invalid in
> >> case of a nonblocking modeset, page flip enabling/disabling planes or any
> >> other reason.
> >>
> >> When the crtc is disabled or during a modeset the intermediate watermarks
> >> don't need to be programmed separately, and could be directly assigned
> >> to the optimal watermarks.
> >>
> >> CXSR must always be disabled in the intermediate case for modesets, else
> >> we get a WARN for vblank wait timeout.
> >>
> >> Also rename crtc_state to new_crtc_state, to distinguish it from the old state.
> >>
> >> Changes since v1:
> >> - Use intel_atomic_get_old_crtc_state. (ville)
> >> Changes since v2:
> >> - Always unset cxsr during modeset.
> >>
> >> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> > I was going to try and figure out how/if these get rid of the unclaimed
> > reg warns, but I didn't quite get that far. I did spot a few other
> > buglets in the wm code though (I'll send fixes for those at some point).
> >
> > Anyways, these patches make sense to me, so for the series
> > Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Seems Chris Wilson already beat us to it..
> 
> https://intel-gfx-ci.01.org/tree/drm-tip/igt@kms_pipe_crc_basic@suspend-read-crc-pipe-b.html
> was gone with
> 
> commit 1a1f12872edcd5e425b668a35fb23548cfa918ef
> Author: Chris Wilson <chris at chris-wilson.co.uk <mailto:chris at chris-wilson.co.uk>>
> Date:   Tue Nov 7 14:03:38 2017 +0000
> 
>     drm/i915: Prevent unbounded wm results in g4x_compute_wm()

That patch should be nop. So this is a very surprising result.

> 
> But I think this patch also fixes it in a slightly different way, never using garbage for intermediaries. :-)
> 
> Thanks for review, pushed.
> 
> Cheers,
> ~Maarten

-- 
Ville Syrjälä
Intel OTC