diff options
author | Jos Wang <joswang@lenovo.com> | 2025-02-09 15:19:26 +0800 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-04-11 16:08:32 +0200 |
commit | b4b38ffb38c91afd4dc387608db26f6fc34ed40b (patch) | |
tree | 4c49246f48250e5f0d2b59136ee5d5dc8618614a /drivers/usb/cdns3/cdns3-plat.c | |
parent | aaa8f2e959341fd4a3ccf111500eb1e6176678e0 (diff) |
usb: typec: displayport: Receive DP Status Update NAK request exit dp altmode
Although some Type-C DRD devices that do not support the DP Sink
function (such as Huawei Mate 40Pro), the Source Port initiates
Enter Mode CMD, but the device responds to Enter Mode ACK, the
Source port then initiates DP Status Update CMD, and the device
responds to DP Status Update NAK.
As PD2.0 spec ("6.4.4.3.4 Enter Mode Command"),A DR_Swap Message
Shall Not be sent during Modal Operation between the Port Partners.
At this time, the source port initiates DR_Swap message through the
"echo device > /sys/class/typec/port0/data_role" command to switch
the data role from host to device. The device will initiate a Hard
Reset for recovery, resulting in the failure of data role swap.
Therefore, when DP Status Update NAK is received, Exit Mode CMD is
initiated to exit the currently entered DP altmode.
Signed-off-by: Jos Wang <joswang@lenovo.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20250209071926.69625-1-joswang1221@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/cdns3/cdns3-plat.c')
0 files changed, 0 insertions, 0 deletions