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, 23 Aug 2023 09:13:09 +0000 (11:13 +0200)
commit78e0ea4277546debf7e96797ac3b768539cc44f6
treefb078a91238da2bd0712d5cf6077e45506c1c6da
parent2d6d80127006ae3da26b1f21a65eccf957f2d1e5
tcpm: Avoid soft reset when partner does not support get_status

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