[Intel-gfx] [PATCH 18/23] drm/i915/mtl: DBUF handling is same as adlp

[Matt Roper]

On Wed, Jul 27, 2022 at 06:34:15PM -0700, Radhakrishna Sripada wrote:
> Meteorlake uses a similar DBUF programming as ADL-P.
> Reuse the call flow for meteorlake.

Although the patch below is correct, the commit message and subject line
here are extremely misleading.  MTL uses _very_ different
handling/programming of DBUF (via the new PM demand mechanism).  The
only thing that's actually the same is the computation of which dbufs
will be enabled (which is all this patch deals with).

> 
> Bspec: 49255
> 
> Cc: Matt Roper <matthew.d.roper at intel.com>
> Original Author: Caz Yokoyama
> Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_pm.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 58a3c72418a7..d73be4bbaaa3 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -4934,7 +4934,7 @@ static u8 skl_compute_dbuf_slices(struct intel_crtc *crtc, u8 active_pipes, bool
>  
>  	if (IS_DG2(dev_priv))
>  		return dg2_compute_dbuf_slices(pipe, active_pipes, join_mbus);
> -	else if (IS_ALDERLAKE_P(dev_priv))
> +	else if (DISPLAY_VER(dev_priv) >= 14 || IS_ALDERLAKE_P(dev_priv))

An alternative would be to just do

        else if (DISPLAY_VER(dev_priv) >= 13)

here since DG2 is already broken out into its own case above.

But either way,

Reviewed-by: Matt Roper <matthew.d.roper at intel.com>

with an updated commit message/subject change.

>  		return adlp_compute_dbuf_slices(pipe, active_pipes, join_mbus);
>  	else if (DISPLAY_VER(dev_priv) == 12)
>  		return tgl_compute_dbuf_slices(pipe, active_pipes, join_mbus);
> -- 
> 2.25.1
> 

-- 
Matt Roper
Graphics Software Engineer
VTT-OSGC Platform Enablement
Intel Corporation