APPLIED [OEM-5.10] Re: [PATCH 1/2][F/G/U/OEM-5.10] UBUNTU: SAUCE: drm/dp/mst: Export drm_dp_get_vc_payload_bw()

[Timo Aaltonen]

On 27.1.2021 8.10, Koba Ko wrote:
> From: Imre Deak <imre.deak at intel.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/1913372
> 
> This function will be needed by the next patch where the driver
> calculates the BW based on driver specific parameters, so export it.
> 
> At the same time sanitize the function params, passing the more natural
> link rate instead of the encoding of the same rate.
> 
> Cc: Lyude Paul <lyude at redhat.com>
> Cc: Ville Syrjala <ville.syrjala at intel.com>
> Cc: <stable at vger.kernel.org>
> Cc: dri-devel at lists.freedesktop.org
> Signed-off-by: Imre Deak <imre.deak at intel.com>
> Reviewed-by: Lyude Paul <lyude at redhat.com>
> Reference: https://patchwork.freedesktop.org/series/86267/
> Signed-off-by: Koba Ko <koba.ko at canonical.com>
> ---
>   drivers/gpu/drm/drm_dp_mst_topology.c | 24 ++++++++++++++++++------
>   include/drm/drm_dp_mst_helper.h       |  1 +
>   2 files changed, 19 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
> index e87542533640..ae6bc2093479 100644
> --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> @@ -3629,14 +3629,26 @@ static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr,
>   	return 0;
>   }
>   
> -static int drm_dp_get_vc_payload_bw(u8 dp_link_bw, u8  dp_link_count)
> +/**
> + * drm_dp_get_vc_payload_bw - get the VC payload BW for an MST link
> + * @rate: link rate in 10kbits/s units
> + * @lane_count: lane count
> + *
> + * Calculate the toal bandwidth of a MultiStream Transport link. The returned
> + * value is in units of PBNs/(timeslots/1 MTP). This value can be used to
> + * convert the number of PBNs required for a given stream to the number of
> + * timeslots this stream requires in each MTP.
> + */
> +int drm_dp_get_vc_payload_bw(int link_rate, int link_lane_count)
>   {
> -	if (dp_link_bw == 0 || dp_link_count == 0)
> -		DRM_DEBUG_KMS("invalid link bandwidth in DPCD: %x (link count: %d)\n",
> -			      dp_link_bw, dp_link_count);
> +	if (link_rate == 0 || link_lane_count == 0)
> +		DRM_DEBUG_KMS("invalid link rate/lane count: (%d / %d)\n",
> +			      link_rate, link_lane_count);
>   
> -	return dp_link_bw * dp_link_count / 2;
> +	/* See DP v2.0 2.6.4.2, VCPayload_Bandwidth_for_OneTimeSlotPer_MTP_Allocation */
> +	return link_rate * link_lane_count / 54000;
>   }
> +EXPORT_SYMBOL(drm_dp_get_vc_payload_bw);
>   
>   /**
>    * drm_dp_read_mst_cap() - check whether or not a sink supports MST
> @@ -3692,7 +3704,7 @@ int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool ms
>   			goto out_unlock;
>   		}
>   
> -		mgr->pbn_div = drm_dp_get_vc_payload_bw(mgr->dpcd[1],
> +		mgr->pbn_div = drm_dp_get_vc_payload_bw(drm_dp_bw_code_to_link_rate(mgr->dpcd[1]),
>   							mgr->dpcd[2] & DP_MAX_LANE_COUNT_MASK);
>   		if (mgr->pbn_div == 0) {
>   			ret = -EINVAL;
> diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h
> index f5e92fe9151c..bd1c39907b92 100644
> --- a/include/drm/drm_dp_mst_helper.h
> +++ b/include/drm/drm_dp_mst_helper.h
> @@ -783,6 +783,7 @@ drm_dp_mst_detect_port(struct drm_connector *connector,
>   
>   struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port);
>   
> +int drm_dp_get_vc_payload_bw(int link_rate, int link_lane_count);
>   
>   int drm_dp_calc_pbn_mode(int clock, int bpp, bool dsc);
>   
> 

applied to oem-5.10, thanks

-- 
t