[Intel-gfx] [PATCH v6 1/3] drm/dp: DRM DP helper for reading Ignore MSA from DPCD

[Manasi Navare]

@Jani N, could you give an ACK on this if this looks okay, addressed
your review comments regarding the name of the function.
Else I have a r-b functionality wise so good to get merged?

Regards
Manasi

On Fri, Jun 12, 2020 at 04:04:42PM -0700, Manasi Navare wrote:
> DP sink device sets the Ignore MSA bit in its
> DP_DOWNSTREAM_PORT_COUNT register to indicate its ability to
> ignore the MSA video timing parameters and its ability to support
> seamless video timing change over a range of timing exposed by
> DisplayID and EDID.
> This is required for the sink to indicate that it is Adaptive sync
> capable.
> 
> v3:
> * Fi the typo in commit message (Manasi)
> v2:
> * Rename to describe what the function does (Jani Nikula)
> 
> Cc: Jani Nikula <jani.nikula at linux.intel.com>
> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Cc: Harry Wentland <harry.wentland at amd.com>
> Cc: Nicholas Kazlauskas <Nicholas.Kazlauskas at amd.com>
> Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>
> Reviewed-by: Harry Wentland <harry.wentland at amd.com>
> ---
>  include/drm/drm_dp_helper.h | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
> index 1165ec105638..e47dc22ebf50 100644
> --- a/include/drm/drm_dp_helper.h
> +++ b/include/drm/drm_dp_helper.h
> @@ -1457,6 +1457,14 @@ drm_dp_alternate_scrambler_reset_cap(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
>  			DP_ALTERNATE_SCRAMBLER_RESET_CAP;
>  }
>  
> +/* Ignore MSA timing for Adaptive Sync support on DP 1.4 */
> +static inline bool
> +drm_dp_sink_can_do_video_without_timing_msa(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
> +{
> +	return dpcd[DP_DOWN_STREAM_PORT_COUNT] &
> +		DP_MSA_TIMING_PAR_IGNORED;
> +}
> +
>  /*
>   * DisplayPort AUX channel
>   */
> -- 
> 2.19.1
>