On Thu, 2024-03-07 at 19:15 +0200, Ville Syrjälä wrote:
> On Wed, Mar 06, 2024 at 10:34:26AM +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
> >
> > Signed-off-by: Jouni Högander <jouni.hogander@xxxxxxxxx>
> > ---
> > drivers/gpu/drm/i915/display/intel_psr.c | 9 ++++++++-
> > 1 file changed, 8 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_psr.c
> > b/drivers/gpu/drm/i915/display/intel_psr.c
> > index e1df0ece9fa3..e8410e770da8 100644
> > --- a/drivers/gpu/drm/i915/display/intel_psr.c
> > +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> > @@ -1160,6 +1160,9 @@ static bool _lnl_compute_alpm_params(struct
> > intel_dp *intel_dp,
> > * This is not directly mentioned in Bspec. There are 50 us io
> > wake time and 32
> > * us fast wake time. Clearly preharge pulses are not (improperly)
> > included in
> > * 32 us fast wake time. 50 us - 32 us = 18 us.
> > + *
> > + * For DISPLAY_VER >= 20
> > + * RBR 15us, HBR1 11us, higher rates 10us
> > */
> > static int get_io_buffer_wake_time(const struct intel_crtc_state
> > *crtc_state)
> > {
> > @@ -1167,8 +1170,12 @@ static int get_io_buffer_wake_time(const
> > struct intel_crtc_state *crtc_state)
> >
> > if (DISPLAY_VER(i915) < 12)
> > return 18;
> > - else
> > + else if (DISPLAY_VER(i915) < 20 || crtc_state->port_clock >
> > 270000)
> > return 10;
> > + else if (crtc_state->port_clock > 162000)
> > + return 11;
> > + else
> > + return 15;
>
> That's getting rather messy. I think having separate functions for
> skl vs. tgl vs. mtl (assuming the ver==20 is mtl) would be cleaner.
ver == 20 == lnl
ver == 14 == mtl
So you are thinking get_io_buffer_wake_time would do:
if (DISPLAY_VER(i915) >= 20)
lnl_get_io_buffer_wake_time();
else if (DISPLAY_VER(i915) >= 12)
tgl_get_io_buffer_wake_time();
else
skl_get_buffer_wake_time();
?
BR,
Jouni Högander
> And the only one of those that I think deserves a comment is skl
> since
> there we don't get a proper value from bspec directly.
>
> > }
> >
> > static bool _compute_alpm_params(struct intel_dp *intel_dp,
> > --
> > 2.34.1
>
