[PATCH 1/3] drm/i915/psr: LunarLake IO and Fast Wake time line count maximums are 63

[Hogander, Jouni]

On Fri, 2024-05-17 at 06:28 +0000, Shankar, Uma wrote:
> 
> 
> > -----Original Message-----
> > From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf
> > Of Jouni
> > Högander
> > Sent: Friday, May 3, 2024 11:36 AM
> > To: intel-gfx at lists.freedesktop.org
> > Cc: Hogander, Jouni <jouni.hogander at intel.com>
> > Subject: [PATCH 1/3] drm/i915/psr: LunarLake IO and Fast Wake time
> > line count
> > maximums are 63
> > 
> > On LunarLake maximum for IO and Fast Wake times are 63. Take this
> > into
> > account in calculation and when writing the IO Wake lines.
> > 
> > Bspec: 69885, 70294
> > 
> > Signed-off-by: Jouni Högander <jouni.hogander at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_psr.c | 5 +++--
> >  1 file changed, 3 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_psr.c
> > b/drivers/gpu/drm/i915/display/intel_psr.c
> > index f5b33335a9ae..678987bbe168 100644
> > --- a/drivers/gpu/drm/i915/display/intel_psr.c
> > +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> > @@ -1364,8 +1364,9 @@ static bool _compute_alpm_params(struct
> > intel_dp
> > *intel_dp,
> >         fast_wake_time = precharge + preamble + phy_wake +
> >                 tfw_exit_latency;
> > 
> > -       if (DISPLAY_VER(i915) >= 12)
> > -               /* TODO: Check how we can use ALPM_CTL fast wake
> > extended
> > field */
> > +       if (DISPLAY_VER(i915) >= 20)
> > +               max_wake_lines = 63;
> 
> As per spec, hardware will add 5 extra lines to the programmed value.
> For prior platforms it was set to 12 as 7 (3bits) + 5. I guess we
> should make this
> consistent.

Thank you Uma for pointing this out. I have fixed this and the typo you
mentioned on patch 3. Please recheck.

BR,

Jouni Högander
> 
> Regards,
> Uma Shankar
> 
> > +       else if (DISPLAY_VER(i915) >= 12)
> >                 max_wake_lines = 12;
> >         else
> >                 max_wake_lines = 8;
> > --
> > 2.34.1
>