[Intel-gfx] [PATCH] drm/i915: Pretend cursor is always on for ILK-style WM calculations (v2)

[Matt Roper]

On Wed, Feb 03, 2016 at 01:16:38PM +0200, Ville Syrjälä wrote:
> On Tue, Feb 02, 2016 at 10:06:51PM -0800, Matt Roper wrote:
> > Due to our lack of two-step watermark programming, our driver has
> > historically pretended that the cursor plane is always on for the
> > purpose of watermark calculations; this helps avoid serious flickering
> > when the cursor turns off/on (e.g., when the user moves the mouse
> > pointer to a different screen).  That workaround was accidentally
> > dropped as we started working toward atomic watermark updates.  Since we
> > still aren't quite there yet with two-stage updates, we need to
> > resurrect the workaround and treat the cursor as always active.
> > 
> > v2: Tweak cursor width calculations slightly to more closely match the
> >     logic we used before the atomic overhaul began.  (Ville)
> > 
> > Cc: simdev11 at outlook.com
> > Cc: manfred.kitzbichler at gmail.com
> > Reported-by: simdev11 at outlook.com
> > Reported-by: manfred.kitzbichler at gmail.com
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93892
> > Fixes: 43d59eda1 ("drm/i915: Eliminate usage of plane_wm_parameters from ILK-style WM code (v2)")
> > Signed-off-by: Matt Roper <matthew.d.roper at intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_pm.c | 15 ++++++++++-----
> >  1 file changed, 10 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> > index 31bc4ea..5888632 100644
> > --- a/drivers/gpu/drm/i915/intel_pm.c
> > +++ b/drivers/gpu/drm/i915/intel_pm.c
> > @@ -1799,16 +1799,21 @@ static uint32_t ilk_compute_cur_wm(const struct intel_crtc_state *cstate,
> >  				   const struct intel_plane_state *pstate,
> >  				   uint32_t mem_value)
> >  {
> > -	int cpp = pstate->base.fb ?
> > -		drm_format_plane_cpp(pstate->base.fb->pixel_format, 0) : 0;
> > +	/*
> > +	 * We treat the cursor plane as always-on for the purposes of watermark
> > +	 * calculation.  Until we have two-stage watermark programming merged,
> > +	 * this is necessary to avoid flickering.
> > +	 */
> > +	int cpp = 4;
> > +	int width = pstate->visible ? pstate->base.crtc_w : 64;
> >  
> > -	if (!cstate->base.active || !pstate->visible)
> > +	if (!cstate->base.active)
> >  		return 0;
> >  
> > +
> 
> Stray whitespace.
> 
> Otherwise lgtm
> Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

Whitespace fixed and pushed to dinq.  Also added a Cc: for -fixes since
this is relevant to 4.5.

Thanks for the review.


Matt

> 
> >  	return ilk_wm_method2(ilk_pipe_pixel_rate(cstate),
> >  			      cstate->base.adjusted_mode.crtc_htotal,
> > -			      drm_rect_width(&pstate->dst),
> > -			      cpp, mem_value);
> > +			      width, cpp, mem_value);
> >  }
> >  
> >  /* Only for WM_LP. */
> > -- 
> > 2.1.4
> > 
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> -- 
> Ville Syrjälä
> Intel OTC

-- 
Matt Roper
Graphics Software Engineer
IoTG Platform Enabling & Development
Intel Corporation
(916) 356-2795