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Commit c1e5c2f0 authored by Pablo Sun's avatar Pablo Sun Committed by Greg Kroah-Hartman
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usb: typec: altmodes/displayport: correct pin assignment for UFP receptacles



Fix incorrect pin assignment values when connecting to a monitor with
Type-C receptacle instead of a plug.

According to specification, an UFP_D receptacle's pin assignment
should came from the UFP_D pin assignments field (bit 23:16), while
an UFP_D plug's assignments are described in the DFP_D pin assignments
(bit 15:8) during Mode Discovery.

For example the LG 27 UL850-W is a monitor with Type-C receptacle.
The monitor responds to MODE DISCOVERY command with following
DisplayPort Capability flag:

        dp->alt->vdo=0x140045

The existing logic only take cares of UPF_D plug case,
and would take the bit 15:8 for this 0x140045 case.

This results in an non-existing pin assignment 0x0 in
dp_altmode_configure.

To fix this problem a new set of macros are introduced
to take plug/receptacle differences into consideration.

Fixes: 0e3bb7d6 ("usb: typec: Add driver for DisplayPort alternate mode")
Cc: stable@vger.kernel.org
Co-developed-by: default avatarPablo Sun <pablo.sun@mediatek.com>
Co-developed-by: default avatarMacpaul Lin <macpaul.lin@mediatek.com>
Reviewed-by: default avatarGuillaume Ranquet <granquet@baylibre.com>
Reviewed-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: default avatarPablo Sun <pablo.sun@mediatek.com>
Signed-off-by: default avatarMacpaul Lin <macpaul.lin@mediatek.com>
Link: https://lore.kernel.org/r/20220804034803.19486-1-macpaul.lin@mediatek.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 1bcafc04
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