Re: [PATCH 1/4] drm/i915/dp: Fix readback for target_rr in Adaptive Sync SDP

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Tue, Nov 11, 2025 at 03:00:04PM +0530, Ankit Nautiyal wrote:
> Correct the bit-shift logic to properly readback the 10 bit target_rr from
> DB3 and DB4.
> 
> v2: Align the style with readback for vtotal. (Ville)
> 
> Fixes: 12ea89291603 ("drm/i915/dp: Add Read/Write support for Adaptive Sync SDP")
> Cc: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
> Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_dp.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 0ec82fcbcf48..92a553a76b57 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -4997,7 +4997,7 @@ int intel_dp_as_sdp_unpack(struct drm_dp_as_sdp *as_sdp,
>  	as_sdp->length = sdp->sdp_header.HB3 & DP_ADAPTIVE_SYNC_SDP_LENGTH;
>  	as_sdp->mode = sdp->db[0] & DP_ADAPTIVE_SYNC_SDP_OPERATION_MODE;
>  	as_sdp->vtotal = (sdp->db[2] << 8) | sdp->db[1];
> -	as_sdp->target_rr = (u64)sdp->db[3] | ((u64)sdp->db[4] & 0x3);
> +	as_sdp->target_rr = ((sdp->db[4] & 0x3) << 8) | sdp->db[3];
>  	as_sdp->target_rr_divider = sdp->db[4] & 0x20 ? true : false;
>  
>  	return 0;
> -- 
> 2.45.2

-- 
Ville Syrjälä
Intel