Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider: - [Medium] The logic for identifying a Virtual DPCD downstream port misses the required DPCD_Revision check, causing standard legacy converters to be incorrectly identified as Virtual DPCDs. --
commit 659313a54262ef8ae8960a7c3b7925da1958206b Author: Xiao Lu <[email protected]> drm/dp/mst: recognize DP-to-HDMI PCON as virtual DPCD in DP-to-DP topology This commit updates drm_dp_mst_is_virtual_dpcd() to accept legacy converters as a valid downstream peer type. This allows the driver to correctly identify PCON devices that advertise their downstream HDMI sink port using DP_PEER_DEVICE_DP_LEGACY_CONV. > diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c > b/drivers/gpu/drm/display/drm_dp_mst_topology.c > index 7ce9e212770ad..5f15d9313a20e 100644 > --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c > +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c > @@ -6047,7 +6047,8 @@ static bool drm_dp_mst_is_virtual_dpcd(struct > drm_dp_mst_port *port) > port->mstb && > port->mstb->num_ports == 2) { > list_for_each_entry(downstream_port, &port->mstb->ports, next) { > - if (downstream_port->pdt == DP_PEER_DEVICE_SST_SINK && > + if ((downstream_port->pdt == DP_PEER_DEVICE_SST_SINK || > + downstream_port->pdt == > DP_PEER_DEVICE_DP_LEGACY_CONV) && > !downstream_port->input) { > mutex_unlock(&port->mgr->lock); > return true; [Severity: Medium] Will this incorrectly identify standard legacy converters as Virtual DPCDs? The commit message notes that Virtual DPCD presence for legacy converters is indicated by a non-zero DPCD_Revision (VESA SCR Option 2), but the added logic accepts DP_PEER_DEVICE_DP_LEGACY_CONV without verifying if downstream_port->dpcd_rev != 0. Could this cause the driver to improperly set passthrough_aux and attempt DPCD reads on a standard DP-to-VGA/DVI/HDMI converter (with dpcd_rev == 0) connected to a 2-port MST branch device, resulting in AUX timeouts or link training failures? -- Sashiko AI review · https://sashiko.dev/#/patchset/[email protected]?part=1
