16cd3c6701
When a channel is asked to be stopped (teardown) and we do not have active descriptor to receive stale data buffered on the remote side then the teardown will not complete as UDMA needs a descriptor to be able to flush out the DMA pipe. The peer is trying to push the data to UDMA in teardown, but UDMA is pushing back because it has no descriptor which would allow it to drain the data. The workaround is to create 1K 'trashcan' to receive the discarded data and set up descriptors for packet and TR mode channels. When a channel is stopped and there is no active descriptor then a descriptor is pushed to the ring for UDMA before the teardown is initiated. Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> Link: https://lore.kernel.org/r/20200214091441.27535-3-peter.ujfalusi@ti.com Signed-off-by: Vinod Koul <vkoul@kernel.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.