On Mon, 2021-01-25 at 19:36 +0200, Imre Deak wrote: > 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@xxxxxxxxxx> > Cc: Ville Syrjala <ville.syrjala@xxxxxxxxx> > Cc: <stable@xxxxxxxxxxxxxxx> > Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx > Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx> > --- > 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 475939138b21..dc96cbf78cc6 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 s/toal/total/ With that fixed, this patch is: Reviewed-by: Lyude Paul <lyude@xxxxxxxxxx> > + * 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); > -- Sincerely, Lyude Paul (she/her) Software Engineer at Red Hat Note: I deal with a lot of emails and have a lot of bugs on my plate. If you've asked me a question, are waiting for a review/merge on a patch, etc. and I haven't responded in a while, please feel free to send me another email to check on my status. I don't bite! _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel