linux-kernel - Re: [RFC PATCH 0/7] usb: typec: ucsi: Polling the alt modes and PDOs

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Date:   Tue, 08 Jun 2021 21:32:01 +0200
From:   Benjamin Berg <bberg@...hat.com>
To:     Heikki Krogerus <heikki.krogerus@...ux.intel.com>
Cc:     linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH 0/7] usb: typec: ucsi: Polling the alt modes and PDOs

On Tue, 2021-06-08 at 09:54 +0300, Heikki Krogerus wrote:
> On Tue, Jun 08, 2021 at 09:42:09AM +0300, Heikki Krogerus wrote:
> > Please check does the partner device get removed. What do you have
> > under /sys/class/typec after that happens?
> 
> Oh yes. Could you also share the trace output when that happens?
> 
>         cd /sys/kernel/debug/tracing
>         echo 1 > events/ucsi/enable
>         # now reproduce the issue
>         cat trace > ucsi.trace

So, the partner device is still there when this happens (see below). I
also only see a single event in the trace for the fast plug/unplug
case:
   kworker/u16:8-1771    [003] .... 18848.872145: ucsi_connector_change: port1 status: change=4a04, opmode=5, connected=1, sourcing=0, partner_flags=1, partner_type=1, request_data_obj=1304b12c, BC status=1

The typec port/partner states is:

port1-partner/accessory_mode:none
port1-partner/supports_usb_power_delivery:no
port1-partner/uevent:DEVTYPE=typec_partner
port1-partner/usb_power_delivery_revision:0.0

and

port0/data_role:host [device]
port0/power_operation_mode:default
port0/power_role:source [sink]
port0/supported_accessory_modes:none
port0/uevent:DEVTYPE=typec_port
port0/uevent:TYPEC_PORT=port0
port0/usb_power_delivery_revision:2.0
port0/usb_typec_revision:1.0
port0/vconn_source:no
port1/data_role:host [device]
port1/power_operation_mode:3.0A
port1/power_role:source [sink]
port1/supported_accessory_modes:none
port1/uevent:DEVTYPE=typec_port
port1/uevent:TYPEC_PORT=port1
port1/usb_power_delivery_revision:2.0
port1/usb_typec_revision:1.0
port1/vconn_source:no

Note that for a normal plug I am usually getting a second event. This
second event is occasionally missing though:
  kworker/u16:38-1800    [001] .... 19522.325885: ucsi_connector_change: port1 status: change=4a04, opmode=5, connected=1, sourcing=0, partner_flags=1, partner_type=1, request_data_obj=1304b12c, BC status=1
  kworker/u16:38-1800    [004] .... 19522.552613: ucsi_connector_change: port1 status: change=0044, opmode=3, connected=1, sourcing=0, partner_flags=1, partner_type=1, request_data_obj=1304b12c, BC status=1

and a working unplug consistently looks like:
   kworker/u16:8-1771    [003] .... 19670.020085: ucsi_connector_change: port1 status: change=4804, opmode=0, connected=0, sourcing=0, partner_flags=1, partner_type=1, request_data_obj=1304b12c, BC status=0

Benjamin

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