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

[Hogander, Jouni]

On Fri, 2024-03-08 at 16:56 +0200, Ville Syrjälä wrote:
> 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 at 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.

Referring our offline discussion with HW folks: It seems 10 us is ok
for LNL as well. What do you think if we just drop this patch as it
seems to be incorrect?

Can you also provide you rb to patch 5 in this set?

BR,

Jouni Högander

> 
> > 
> > > +
> > >  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
>