Re: [Intel-gfx] [PATCH] drm/i915/mtl: Copy c10 phy pll sw state from master to slave for bigjoiner

["Lisovskiy, Stanislav" <stanislav.lisovskiy@intel.com>]

On Fri, Apr 21, 2023 at 03:19:42PM +0300, Ville Syrjälä wrote:
> On Fri, Apr 21, 2023 at 02:37:11PM +0300, Lisovskiy, Stanislav wrote:
> > On Fri, Apr 21, 2023 at 12:26:08PM +0300, Ville Syrjälä wrote:
> > > On Fri, Apr 21, 2023 at 11:35:20AM +0300, Stanislav Lisovskiy wrote:
> > > > We try to verify pll registers in sw state for slave crtc with the hw state.
> > > > However in case of bigjoiner we don't calculate those at all, so this verification
> > > > will then always fail.
> > > > So we should either skip the verification for Bigjoiner slave crtc or copy sw state
> > > > from master crtc.
> > > > 
> > > > Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
> > > > ---
> > > >  drivers/gpu/drm/i915/display/intel_display.c | 1 +
> > > >  1 file changed, 1 insertion(+)
> > > > 
> > > > diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> > > > index bf391a6cd8d6..83c98791fea3 100644
> > > > --- a/drivers/gpu/drm/i915/display/intel_display.c
> > > > +++ b/drivers/gpu/drm/i915/display/intel_display.c
> > > > @@ -4556,6 +4556,7 @@ copy_bigjoiner_crtc_state_modeset(struct intel_atomic_state *state,
> > > >  	drm_mode_copy(&slave_crtc_state->hw.adjusted_mode,
> > > >  		      &master_crtc_state->hw.adjusted_mode);
> > > >  	slave_crtc_state->hw.scaling_filter = master_crtc_state->hw.scaling_filter;
> > > > +	slave_crtc_state->cx0pll_state = master_crtc_state->cx0pll_state;
> > > 
> > > Wrong place. Also we're already copying dpll_hw_state which is in the
> > > same union, and on first blush looks bigger than this thing. So why is
> > > that not working?
> > 
> > No we aren't copying it, we are "saving" it earlier, however it doesn't help at all:
> > 
> > /* preserve some things from the slave's original crtc state */
> > saved_state->uapi = slave_crtc_state->uapi;
> > saved_state->scaler_state = slave_crtc_state->scaler_state;
> > saved_state->shared_dpll = slave_crtc_state->shared_dpll;
> > saved_state->dpll_hw_state = slave_crtc_state->dpll_hw_state;
> 
> Hmm. How is anything at all working if we keep this around
> from the old state?
> 
> Looks like I probably broke this in
> commit 0ff0e219d9b8 ("drm/i915: Compute clocks earlier")
> and somehow no one has noticed.
> 
> The correct fix would seem to be to just nuke that
> dpll_hw_state preservation above.

Need to ask for this machine, where this is reproducible and
check if that helps..

Stan

> 
> 
> > saved_state->crc_enabled = slave_crtc_state->crc_enabled;
> > 
> > intel_crtc_free_hw_state(slave_crtc_state);
> > memcpy(slave_crtc_state, saved_state, sizeof(*slave_crtc_state));
> > kfree(saved_state);
> > 
> > /* Re-init hw state */
> > memset(&slave_crtc_state->hw, 0, sizeof(slave_crtc_state->hw));
> > slave_crtc_state->hw.enable = master_crtc_state->hw.enable;
> > slave_crtc_state->hw.active = master_crtc_state->hw.active;
> > 
> > because I guess it just didn't have that stuff initially.
> > 
> > It starts to work without those verify WARN's only if I copy it from master_crtc_state.
> > 
> > Stan
> > 
> > > 
> > > >  
> > > >  	copy_bigjoiner_crtc_state_nomodeset(state, slave_crtc);
> > > >  
> > > > -- 
> > > > 2.37.3
> > > 
> > > -- 
> > > Ville Syrjälä
> > > Intel
> 
> -- 
> Ville Syrjälä
> Intel