[Intel-gfx] [PATCH] drm/i915/gen9: Give one extra block per line for SKL plane WM calculations

[Zanoni, Paulo R]

Em Qui, 2016-08-04 às 16:51 -0700, Matt Roper escreveu:
> On Thu, Aug 04, 2016 at 07:36:15PM -0400, Lyude wrote:
> > 
> > Reviewed-by: Lyude <cpaul at redhat.com>
> 
> Merged to dinq.  Thanks for the quick review.

Regression? This patch makes my SKL machine fail any modesets. I now
boot to a blinking screen where X keeps trying to start and fails.

Xorg.0.log gives me:
[   273.512] (EE) modeset(0): failed to set mode: Invalid argument


On the dmesg side, these are the more suspicious messages:

[  273.583659] [drm:skl_compute_plane_wm] Requested display
configuration exceeds system watermark limitations
[  273.583663] [drm:skl_compute_plane_wm] Plane 1.0: blocks required =
4/0, lines required = 1/31


I tried applying Lyude's series to nightly to see if it fixes
something, but it looks like patch 2 doesn't apply.

> 
> 
> Matt
> 
> > 
> > 
> > On Thu, 2016-08-04 at 14:08 -0700, Matt Roper wrote:
> > > 
> > > The bspec was updated a couple weeks ago to add an extra block
> > > per
> > > line
> > > to plane watermark calculations for linear pixel formats.
> > > 
> > > Bspec update 115327 description:
> > >   "Gen9+ - Updated the plane blocks per line calculation for
> > > linear
> > >   cases. Adds +1 for all linear cases to handle the non-block
> > > aligned
> > >   stride cases."
> > > 
> > > Cc: Lyude <cpaul at redhat.com>
> > > Signed-off-by: Matt Roper <matthew.d.roper at intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/intel_pm.c | 2 ++
> > >  1 file changed, 2 insertions(+)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/intel_pm.c
> > > b/drivers/gpu/drm/i915/intel_pm.c
> > > index 4317cdf..6bd352a 100644
> > > --- a/drivers/gpu/drm/i915/intel_pm.c
> > > +++ b/drivers/gpu/drm/i915/intel_pm.c
> > > @@ -3352,6 +3352,8 @@ static uint32_t skl_wm_method2(uint32_t
> > > pixel_rate, uint32_t pipe_htotal,
> > >  		plane_bytes_per_line *= 4;
> > >  		plane_blocks_per_line =
> > > DIV_ROUND_UP(plane_bytes_per_line, 512);
> > >  		plane_blocks_per_line /= 4;
> > > +	} else if (tiling == DRM_FORMAT_MOD_NONE) {
> > > +		plane_blocks_per_line =
> > > DIV_ROUND_UP(plane_bytes_per_line, 512) + 1;
> > >  	} else {
> > >  		plane_blocks_per_line =
> > > DIV_ROUND_UP(plane_bytes_per_line, 512);
> > >  	}
> > -- 
> > Cheers,
> > 	Lyude
>