On Fri, Mar 08, 2024 at 08:39:36AM +0000, Hogander, Jouni wrote:
> 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
Hmm. I thought 14 was just bumped to 20 because someone didn't
understand that 0x14==20.
>
> 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();
>
> ?
Yeah. Personally I would also drop the "get_" part from the function
names. That just makes me think it's getting a reference or something.
--
Ville Syrjälä
Intel
