Re: [PATCH] drm/i915/skl: Correct other-pipe watermark update condition check

[Daniel Vetter <daniel@ffwll.ch>]

On Mon, Oct 19, 2015 at 04:00:18PM +0300, Ville Syrjälä wrote:
> On Mon, Oct 19, 2015 at 11:29:59AM +0200, Daniel Vetter wrote:
> > On Mon, Sep 21, 2015 at 11:32:44PM +0530, Kumar, Mahesh wrote:
> > > If ddb allocation for planes in current CRTC is changed, that doesn't
> > > lead to ddb allocation change for other CRTCs, because our DDB allocation
> > > is not dynamic according to plane parameters, ddb is allocated according
> > > to number of CRTC enabled, & divided equally among CTRC's.
> > > 
> > > In current condition check during Watermark calculation, if number of
> > > plane/ddb allocation changes for current CRTC, Watermark for other pipes
> > > are recalculated. But there is no change in DDB allocation of other pipe
> > > so watermark is also not changed, This leads to warning messages.
> > > WARN_ON(!wm_changed)
> > > 
> > > This patch corrects this and check if DDB allocation for pipes is changed,
> > > then only recalculate watermarks.
> > > 
> > > Signed-off-by: Kumar, Mahesh <mahesh1.kumar@intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/intel_pm.c | 12 +++++-------
> > >  1 file changed, 5 insertions(+), 7 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> > > index 62de97e..a1ed920 100644
> > > --- a/drivers/gpu/drm/i915/intel_pm.c
> > > +++ b/drivers/gpu/drm/i915/intel_pm.c
> > > @@ -3127,14 +3127,12 @@ static bool skl_ddb_allocation_changed(const struct skl_ddb_allocation *new_ddb,
> > >  	struct drm_device *dev = intel_crtc->base.dev;
> > >  	struct drm_i915_private *dev_priv = dev->dev_private;
> > >  	const struct skl_ddb_allocation *cur_ddb = &dev_priv->wm.skl_hw.ddb;
> > > -	enum pipe pipe = intel_crtc->pipe;
> > > -
> > > -	if (memcmp(new_ddb->plane[pipe], cur_ddb->plane[pipe],
> > > -		   sizeof(new_ddb->plane[pipe])))
> > > -		return true;
> > >  
> > > -	if (memcmp(&new_ddb->cursor[pipe], &cur_ddb->cursor[pipe],
> > > -		    sizeof(new_ddb->cursor[pipe])))
> > > +	/*
> > > +	 * If ddb allocation of pipes chenged, it may require recalculation of
> > > +	 * watermarks
> > > +	 */
> > > +	if (memcmp(new_ddb->pipe, cur_ddb->pipe, sizeof(new_ddb->pipe)))
> > >  		return true;
> > 
> > I still have the cursor code here, this patch needs to be rebased.
> 
> I suppose you mean you have the other cursor code there, cause this one
> has it too, just looking a bit different.

Hm yeah right, just shows how little I understand from the wm code details
;-)

Anyway, please rebase since I can't make this one fit without too much
risk of me fumbling things.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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