[Intel-gfx] [PATCH v3] drm/i915/psr: Update PSR2 resolution check for Cannonlake

[Pandiyan, Dhinakaran]

On Tue, 2018-03-06 at 23:24 +0200, Ville Syrjälä wrote:
> On Tue, Mar 06, 2018 at 08:45:44PM +0000, Pandiyan, Dhinakaran wrote:
> > 
> > 
> > 
> > On Tue, 2018-03-06 at 22:38 +0200, Ville Syrjälä wrote:
> > > On Tue, Mar 06, 2018 at 12:33:55PM -0800, Dhinakaran Pandiyan wrote:
> > > > In fact, apply the Cannonlake resolution check for all >= Gen-10 platforms
> > > > to be safe.
> > > > 
> > > > v3: Update GLK too. (Ville)
> > > >     Longer variable names.
> > > >     if-else in place of ternary operator.
> > > > v2: Use local variables for resolution limits and print them (Ville)
> > > > 
> > > > Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > > > Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> > > > Cc: Elio Martinez Monroy <elio.martinez.monroy at intel.com>
> > > > Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
> > > > ---
> > > >  drivers/gpu/drm/i915/intel_psr.c | 21 +++++++++++++++------
> > > >  1 file changed, 15 insertions(+), 6 deletions(-)
> > > > 
> > > > diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
> > > > index 05770790a4e9..23175c5c4a50 100644
> > > > --- a/drivers/gpu/drm/i915/intel_psr.c
> > > > +++ b/drivers/gpu/drm/i915/intel_psr.c
> > > > @@ -451,8 +451,9 @@ static bool intel_psr2_config_valid(struct intel_dp *intel_dp,
> > > >  {
> > > >  	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
> > > >  	struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
> > > > -	const struct drm_display_mode *adjusted_mode =
> > > > -		&crtc_state->base.adjusted_mode;
> > > > +	int crtc_hdisplay = crtc_state->base.adjusted_mode.crtc_hdisplay;
> > > > +	int crtc_vdisplay = crtc_state->base.adjusted_mode.crtc_vdisplay;
> > >             ^^^^^
> > > The crtc_ prefix is pretty much redundant.
> > 
> > display_mode has members named vdisplay and hdisplay and this avoids any
> > potential confusion.
> > 
> > 
> > > 
> > > > +	int psr_max_h = 0, psr_max_v = 0;
> > > 
> > > And this still reads as "max height" to my brain, but meh.
> > 
> > And here I thought this version leaves no room for confusion :) I should
> > just ask someone else to write this patch.
> > 
> > > 
> > > >  
> > > >  	/*
> > > >  	 * FIXME psr2_support is messed up. It's both computed
> > > > @@ -462,10 +463,18 @@ static bool intel_psr2_config_valid(struct intel_dp *intel_dp,
> > > >  	if (!dev_priv->psr.psr2_support)
> > > >  		return false;
> > > >  
> > > > -	/* PSR2 is restricted to work with panel resolutions up to 3640x2304 */
> > > > -	if (adjusted_mode->crtc_hdisplay > 3640 ||
> > > > -	    adjusted_mode->crtc_vdisplay > 2304) {
> > > > -		DRM_DEBUG_KMS("PSR2 not enabled, panel resolution too big\n");
> > > > +	if (INTEL_GEN(dev_priv) >= 10 || IS_GEMINILAKE(dev_priv)) {
> > > > +		psr_max_h = 4096;
> > > > +		psr_max_v = 2304;
> > > > +	} else if (IS_GEN9(dev_priv)) {
> > > > +		psr_max_h = 3640;
> > > > +		psr_max_v = 2304;
> > > > +	}
> > > 
> > > pre-SKL?
> > 
> > No PSR2 on pre-skl
> 
> OK. I'd drop the IS_GEN9 then. Would be less confusing for my brain at
> least.
> 
> > 
> > If we do somehow end up here, returning false and printing a debug
> > message will be useful.
> 
> Seems a bit overly protective. The has_psr2 check is just above. IMO

A recent patch that added this function had a version without the
has_psr2 check. So, I am just paranoid a similar patch might slip
through and the meaning of that flag is inconsistent too. But, I get the
idea of not adding redundant checks. Let's go with this for now and I'll
remove it when I get around to addressing the FIXME above.

> adding basically dead code "just in case" is not helpful in making the
> code easy to read.
> 
> Since you say pre-skl is not a problem here:
> Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 

Thanks!


> > 
> > > 
> > > > +
> > > > +	if (crtc_hdisplay > psr_max_h || crtc_vdisplay > psr_max_v) {
> > > > +		DRM_DEBUG_KMS("PSR2 not enabled, resolution %dx%d > max supported %dx%d\n",
> > > > +			      crtc_hdisplay, crtc_vdisplay,
> > > > +			      psr_max_h, psr_max_v);
> > > >  		return false;
> > > >  	}
> > > >  
> > > > -- 
> > > > 2.14.1
> > > 
>