Benjamin Berg e15e32d519 usb: typec: ucsi: Work around PPM losing change information
commit 217504a055325fe76ec1142aa15f14d3db77f94f upstream.

Some/many PPMs are simply clearing the change bitfield when a
notification on a port is acknowledge. Unfortunately, doing so means
that any changes between the GET_CONNECTOR_STATUS and ACK_CC_CI commands
is simply lost.

Work around this by re-fetching the connector status afterwards. We can
then infer any changes that we see have happened but that may not be
respresented in the change bitfield.

We end up with the following actions:
 1. UCSI_GET_CONNECTOR_STATUS, store result, update unprocessed_changes
 2. UCSI_GET_CAM_SUPPORTED, discard result
 3. ACK connector change
 4. UCSI_GET_CONNECTOR_STATUS, store result
 5. Infere lost changes by comparing UCSI_GET_CONNECTOR_STATUS results
 6. If PPM reported a new change, then restart in order to ACK
 7. Process everything as usual.

The worker is also changed to re-schedule itself if a new change
notification happened while it was running.

Doing this fixes quite commonly occurring issues where e.g. the UCSI
power supply would remain online even thought the ThunderBolt cable was
unplugged.

Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Benjamin Berg <bberg@redhat.com>
Link: https://lore.kernel.org/r/20201009144047.505957-3-benjamin@sipsolutions.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-03 10:09:30 +02:00
2021-09-03 10:09:21 +02:00
2020-10-17 11:18:18 -07:00
2021-08-26 08:51:21 -04:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
Description
No description provided
Readme 5.7 GiB
Languages
C 97.6%
Assembly 1%
Shell 0.5%
Python 0.3%
Makefile 0.3%