Merge series from Peter Ujfalusi <peter.ujfalusi@linux.intel.com>:
The Nullity of sps->cstream needs to be checked in sof_ipc_msg_data() and not
assume that it is not NULL.
The sps->stream must be cleared to NULL on close since this is used as a check
to see if we have active PCM stream.
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 reStructuredText 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.
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