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Commit 9b5d37d3 authored by Prashant Malani's avatar Prashant Malani Committed by Greg Kroah-Hartman
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usb: typec: altmodes/displayport: Fix probe pin assign check 



commit 54e5c00a4eb0a4c663445b245f641bbfab142430 upstream.

While checking Pin Assignments of the port and partner during probe, we
don't take into account whether the peripheral is a plug or receptacle.

This manifests itself in a mode entry failure on certain docks and
dongles with captive cables. For instance, the Startech.com Type-C to DP
dongle (Model #CDP2DP) advertises its DP VDO as 0x405. This would fail
the Pin Assignment compatibility check, despite it supporting
Pin Assignment C as a UFP.

Update the check to use the correct DP Pin Assign macros that
take the peripheral's receptacle bit into account.

Fixes: c1e5c2f0cb8a ("usb: typec: altmodes/displayport: correct pin assignment for UFP receptacles")
Cc: stable@vger.kernel.org
Reported-by: default avatarDiana Zigterman <dzigterman@chromium.org>
Signed-off-by: default avatarPrashant Malani <pmalani@chromium.org>
Link: https://lore.kernel.org/r/20230208205318.131385-1-pmalani@chromium.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d9758f7d

drivers/usb/typec/altmodes/displayport.c

+4 −4
Original line number Diff line number Diff line
@@ -522,10 +522,10 @@ int dp_altmode_probe(struct typec_altmode *alt) 
	/* FIXME: Port can only be DFP_U. */



	/* Make sure we have compatiple pin configurations */

	if (!(DP_CAP_DFP_D_PIN_ASSIGN(port->vdo) &

	      DP_CAP_UFP_D_PIN_ASSIGN(alt->vdo)) &&

	    !(DP_CAP_UFP_D_PIN_ASSIGN(port->vdo) &

	      DP_CAP_DFP_D_PIN_ASSIGN(alt->vdo)))

	if (!(DP_CAP_PIN_ASSIGN_DFP_D(port->vdo) &

	      DP_CAP_PIN_ASSIGN_UFP_D(alt->vdo)) &&

	    !(DP_CAP_PIN_ASSIGN_UFP_D(port->vdo) &

	      DP_CAP_PIN_ASSIGN_DFP_D(alt->vdo)))

		return -ENODEV;



	ret = sysfs_create_group(&alt->dev.kobj, &dp_altmode_group);