f8242f554c
commit 8c9b3caab3ac26db1da00b8117901640c55a69dd upstream.
It's possible that the interrupt handler for the UCSI driver signals a
connector changes after the handler clears the PENDING bit, but before
it has sent the acknowledge request. The result is that the handler is
invoked yet again, to ack the same connector change.
At least some versions of the Qualcomm UCSI firmware will not handle the
second - "spurious" - acknowledgment gracefully. So make sure to not
clear the pending flag until the change is acknowledged.
Any connector changes coming in after the acknowledgment, that would
have the pending flag incorrectly cleared, would afaict be covered by
the subsequent connector status check.
Fixes: 217504a05532 ("usb: typec: ucsi: Work around PPM losing change information")
Cc: stable <stable@vger.kernel.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-By: Benjamin Berg <bberg@redhat.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20210516040953.622409-1-bjorn.andersson@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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.