Re: [PATCH v5 4/5] drm/i915/psr: Add IO buffer wake times for LunarLake and beyond

From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: "Jouni Högander" <jouni.hogander@intel.com>
Cc: intel-gfx@lists.freedesktop.org,
	Jani Nikula <jani.nikula@linux.intel.com>
Subject: Re: [PATCH v5 4/5] drm/i915/psr: Add IO buffer wake times for LunarLake and beyond
Date: Fri, 8 Mar 2024 16:56:01 +0200	[thread overview]
Message-ID: <ZesnAUVANrVYVXwq@intel.com> (raw)
In-Reply-To: <ZesjOx-OjJ4qT4wz@intel.com>

On Fri, Mar 08, 2024 at 04:39:55PM +0200, Ville Syrjälä wrote:
> On Fri, Mar 08, 2024 at 01:00:38PM +0200, Jouni Högander wrote:
> > IO buffer wake time used for IO wake calculation is dependent on port clock
> > on LunarLake and beyond. Take this into account in get_io_buffer_wake_time.
> > 
> > Bspec: 65450
> > 
> > v2: add own io_wake_time helper for LunarLake
> > 
> > Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_psr.c | 14 +++++++++++++-
> >  1 file changed, 13 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
> > index 747761efa4be..e3daaf05d640 100644
> > --- a/drivers/gpu/drm/i915/display/intel_psr.c
> > +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> > @@ -1165,11 +1165,23 @@ static int tgl_io_buffer_wake_time(void)
> >  	return 10;
> >  }
> >  
> > +static int lnl_io_buffer_wake_time(int port_clock)
> > +{
> > +	if (port_clock > 270000)
> > +		return 10;
> > +	else if (port_clock > 162000)
> > +		return 11;
> > +	else
> > +		return 15;
> > +}
> 
> These numbers are only listed in the MTL section of bspec. There
> is nothing like this in the LNL PHY power section AFAICS.

Windows appears to use fixed 12us here.

> 
> > +
> >  static int io_buffer_wake_time(const struct intel_crtc_state *crtc_state)
> >  {
> >  	struct drm_i915_private *i915 = to_i915(crtc_state->uapi.crtc->dev);
> >  
> > -	if (DISPLAY_VER(i915) >= 12)
> > +	if (DISPLAY_VER(i915) >= 20)
> > +		return lnl_io_buffer_wake_time(crtc_state->port_clock);
> > +	else if (DISPLAY_VER(i915) >= 12)
> >  		return tgl_io_buffer_wake_time();
> >  	else
> >  		return skl_io_buffer_wake_time();
> > -- 
> > 2.34.1
> 
> -- 
> Ville Syrjälä
> Intel

-- 
Ville Syrjälä
Intel