On Fri, Dec 15, 2023 at 10:53:31AM +0200, Imre Deak wrote:
> On Fri, Dec 15, 2023 at 10:00:57AM +0200, Mika Kahola wrote:
> > Add clock state verification for C20. Since we
> > are usign either A or B contexts, which are
> > selected based on clock rate, we first need to
> > calculate hw clock and use that clock to select
> > which context we are using.
>
> Could the description be clearer that the patch _fixes_ the context
> selection? (Also the subject line should always say _what_ the patch
> does.)
>
> >
> > Signed-off-by: Mika Kahola <mika.kahola@xxxxxxxxx>
> > ---
> > drivers/gpu/drm/i915/display/intel_cx0_phy.c | 8 +++++++-
> > 1 file changed, 7 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_cx0_phy.c b/drivers/gpu/drm/i915/display/intel_cx0_phy.c
> > index 775c1c4a8978..6757e9f941e4 100644
> > --- a/drivers/gpu/drm/i915/display/intel_cx0_phy.c
> > +++ b/drivers/gpu/drm/i915/display/intel_cx0_phy.c
> > @@ -3079,8 +3079,9 @@ static void intel_c20pll_state_verify(const struct intel_crtc_state *state,
> > const struct intel_c20pll_state *mpll_sw_state = &state->cx0pll_state.c20;
> > bool use_mplla;
> > int i;
> > + int hw_clock = intel_c20pll_calc_port_clock(encoder, mpll_hw_state);
> >
> > - use_mplla = intel_c20_use_mplla(mpll_hw_state->clock);
> > + use_mplla = intel_c20_use_mplla(hw_clock);
>
> It's mpll_hw_state->tx[0] C20_PHY_USE_MPLLB which tells the HW which
> context to use, so I think it's better to use the same condition here.
Yes, one should never assume anything about how the register values
were calculated/etc. That would pretty much defeat the whole purpose
of doing readout and state check.
BTW I don't see even being set anywhere C20_PHY_USE_MPLLB.
Do we not use it or is it encoded in that ugly hex soup in
intel_c20_compute_hdmi_tmds_pll()? Instead of repeating the
mistakes of the VLV PHY code someone should convert that into
human readable form...
>
> > if (use_mplla) {
> > for (i = 0; i < ARRAY_SIZE(mpll_sw_state->mplla); i++) {
> > I915_STATE_WARN(i915, mpll_hw_state->mplla[i] != mpll_sw_state->mplla[i],
> > @@ -3110,6 +3111,11 @@ static void intel_c20pll_state_verify(const struct intel_crtc_state *state,
> > crtc->base.base.id, crtc->base.name, i,
> > mpll_sw_state->cmn[i], mpll_hw_state->cmn[i]);
> > }
> > +
> > + I915_STATE_WARN(i915, hw_clock != mpll_sw_state->clock,
> > + "[CRTC:%d:%s] mismatch in C20: Register CLOCK (expected %d, found %d)",
> > + crtc->base.base.id, crtc->base.name,
> > + mpll_sw_state->clock, hw_clock);
>
> I think the intel_crtc_state::port_clock SW/HW state verification is
> equivalent to the above, but it's good to verify it here as well. I
> would store hw_clock to mpll_hw_state->clock in
> intel_c20pll_readout_hw_state() though.
>
> > }
> >
> > void intel_cx0pll_state_verify(struct intel_atomic_state *state,
> > --
> > 2.34.1
> >
--
Ville Syrjälä
Intel
