Re: [Intel-gfx] [PATCH 3/6] drm/i915: Widen the QGV point mask

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

On Mon, Feb 14, 2022 at 11:18:08AM +0200, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> adlp+ adds some extra bits to the QGV point mask. The code attempts
> to handle that but forgot to actually make sure we can store those
> bits in the bw state. Fix it.
> 
> Cc: stable@vger.kernel.org
> Cc: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
> Fixes: 192fbfb76744 ("drm/i915: Implement PSF GV point support")
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_bw.h | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_bw.h b/drivers/gpu/drm/i915/display/intel_bw.h
> index 46c6eecbd917..0ceaed1c9656 100644
> --- a/drivers/gpu/drm/i915/display/intel_bw.h
> +++ b/drivers/gpu/drm/i915/display/intel_bw.h
> @@ -30,19 +30,19 @@ struct intel_bw_state {
>  	 */
>  	u8 pipe_sagv_reject;
>  
> +	/* bitmask of active pipes */
> +	u8 active_pipes;
> +
>  	/*
>  	 * Current QGV points mask, which restricts
>  	 * some particular SAGV states, not to confuse
>  	 * with pipe_sagv_mask.
>  	 */
> -	u8 qgv_points_mask;
> +	u16 qgv_points_mask;

Weird, that this went unnoticed. Don't we have static analyzer for such
purposes? Wonder if it should catch and warn about this, because in
intel_bw_atomic_check we have u32 bitmask, which is then getting packed
in 8 bit field.
Probably bitmask type width used in intel_bw_atomic_check should match
that one, so that there would be less room for confusion.

Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>

>  
>  	unsigned int data_rate[I915_MAX_PIPES];
>  	u8 num_active_planes[I915_MAX_PIPES];
>  
> -	/* bitmask of active pipes */
> -	u8 active_pipes;
> -
>  	int min_cdclk;
>  };
>  
> -- 
> 2.34.1
>