[Intel-gfx] [PATCH] drm/i915/display: Fix shared dpll mismatch for bigjoiner slave

[Jani Nikula]

On Wed, 14 Jul 2021, Manasi Navare <manasi.d.navare at intel.com> wrote:
> Currently when we do the HW state readout, we dont set the shared dpll to NULL
> for the bigjoiner slave which should not have a DPLL assigned. So it has
> some garbage while the HW state readout is NULL. So explicitly reset
> the shared dpll for bigjoiner slave pipe.
>
> Bug: https://gitlab.freedesktop.org/drm/intel/-/issues/3465
> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Cc: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
> Tested-By: Swati Sharma <swati2.sharma at intel.com>
> Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index 65ddb6ca16e6..c274bfb8e549 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -9006,6 +9006,10 @@ verify_crtc_state(struct intel_crtc *crtc,
>  	if (!new_crtc_state->hw.active)
>  		return;
>  
> +	if (new_crtc_state->bigjoiner_slave)
> +		/* No PLLs set for slave */
> +		pipe_config->shared_dpll = NULL;
> +

I know it's been merged already, but feels wrong to have this in
verify_crtc_state(). Kind of out of place.

BR,
Jani.

>  	intel_pipe_config_sanity_check(dev_priv, pipe_config);
>  
>  	if (!intel_pipe_config_compare(new_crtc_state,

-- 
Jani Nikula, Intel Open Source Graphics Center