mirror of
https://github.com/hardkernel/linux.git
synced 2026-06-07 19:30:30 +09:00
81dc3db4c3
commit f4ecdc352646f7d23f348e5c544dbe3212c94fc8 upstream.
In some cases, there is a small-time gap in which CMD_RING_BUSY can be
cleared by controller but adding command completion event to event ring
will be delayed. As the result driver will return error code.
This behavior has been detected on usbtest driver (test 9) with
configuration including ep1in/ep1out bulk and ep2in/ep2out isoc
endpoint.
Probably this gap occurred because controller was busy with adding some
other events to event ring.
The CMD_RING_BUSY is cleared to '0' when the Command Descriptor has been
executed and not when command completion event has been added to event
ring.
To fix this issue for this test the small delay is sufficient less than
10us) but to make sure the problem doesn't happen again in the future
the patch introduces 10 retries to check with delay about 20us before
returning error code.
Fixes: 3d82904559 ("usb: cdnsp: cdns3 Add main part of Cadence USBSSP DRD Driver")
Cc: stable <stable@kernel.org>
Signed-off-by: Pawel Laszczak <pawell@cadence.com>
Acked-by: Peter Chen <peter.chen@kernel.org>
Link: https://lore.kernel.org/r/PH7PR07MB9538AA45362ACCF1B94EE9B7DD96A@PH7PR07MB9538.namprd07.prod.outlook.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.