tcpm: Avoid soft reset when partner does not support get_status
authorBadhri Jagan Sridharan <badhri@google.com>
Sun, 20 Aug 2023 04:44:48 +0000 (04:44 +0000)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 6 Sep 2023 20:27:02 +0000 (21:27 +0100)
commitdca7c99651415baad8c1fc39214156c7154aaefb
tree6bf54f0eb968b911faec81f837e4277de16703b5
parenta1fc0096921cc329de77b84eb71636b372a46779
tcpm: Avoid soft reset when partner does not support get_status

commit 78e0ea4277546debf7e96797ac3b768539cc44f6 upstream.

When partner does not support get_status message, tcpm right now
responds with soft reset message. This causes PD renegotiation to
happen and resets PPS link. Avoid soft resetting the link when
partner does not support get_status message to mitigate PPS resets.

[  208.926752] Setting voltage/current limit 9500 mV 2450 mA
[  208.930407] set_auto_vbus_discharge_threshold mode:3 pps_active:y vbus:9500 ret:0
[  208.930418] state change SNK_TRANSITION_SINK -> SNK_READY [rev3 POWER_NEGOTIATION]
[  208.930455] AMS POWER_NEGOTIATION finished

// ALERT message from the Source
[  213.948442] PD RX, header: 0x19a6 [1]
[  213.948451] state change SNK_READY -> GET_STATUS_SEND [rev3 GETTING_SOURCE_SINK_STATUS]
[  213.948457] PD TX, header: 0x492
[  213.950402] PD TX complete, status: 0
[  213.950427] pending state change GET_STATUS_SEND -> GET_STATUS_SEND_TIMEOUT @ 60 ms [rev3 GETTING_SOURCE_SINK_STATUS]

// NOT_SUPPORTED from the Source
[  213.959954] PD RX, header: 0xbb0 [1]

// sink sends SOFT_RESET
[  213.959958] state change GET_STATUS_SEND -> SNK_SOFT_RESET [rev3 GETTING_SOURCE_SINK_STATUS]
[  213.959962] AMS GETTING_SOURCE_SINK_STATUS finished
[  213.959964] AMS SOFT_RESET_AMS start
[  213.959966] state change SNK_SOFT_RESET -> AMS_START [rev3 SOFT_RESET_AMS]
[  213.959969] state change AMS_START -> SOFT_RESET_SEND [rev3 SOFT_RESET_AMS]

Cc: stable@vger.kernel.org
Fixes: 8dea75e11380 ("usb: typec: tcpm: Protocol Error handling")
Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20230820044449.1005889-1-badhri@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/usb/typec/tcpm/tcpm.c