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The stop trigger invokes rz_ssi_stop() and rz_ssi_stream_quit().
- The purpose of rz_ssi_stop() is to disable TX/RX, terminate DMA
transactions, and set the controller to idle.
- The purpose of rz_ssi_stream_quit() is to reset the substream-specific
software data by setting strm->running and strm->substream appropriately.
The function rz_ssi_is_stream_running() checks if both strm->substream and
strm->running are valid and returns true if so. Its implementation is as
follows:
static inline bool rz_ssi_is_stream_running(struct rz_ssi_stream *strm)
{
return strm->substream && strm->running;
}
When the controller is configured in full-duplex mode (with both playback
and capture active), the rz_ssi_stop() function does not modify the
controller settings when called for the first substream in the full-duplex
setup. Instead, it simply sets strm->running = 0 and returns if the
companion substream is still running. The following code illustrates this:
static int rz_ssi_stop(struct rz_ssi_priv *ssi, struct rz_ssi_stream *strm)
{
strm->running = 0;
if (rz_ssi_is_stream_running(&ssi->playback) ||
rz_ssi_is_stream_running(&ssi->capture))
return 0;
// ...
}
The controller settings, along with the DMA termination (for the last
stopped substream), are only applied when the last substream in the
full-duplex setup is stopped.
While applying the controller settings only when the last substream stops
is not problematic, terminating the DMA operations for only one substream
causes failures when starting and stopping full-duplex operations multiple
times in a loop.
To address this issue, call dmaengine_terminate_async() for both substreams
involved in the full-duplex setup when the last substream in the setup is
stopped.
Fixes:
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|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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 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.