The recently introduced coef_mutex for Realtek codec seems causing a deadlock when the relevant code is invoked from the power-off state; then the HD-audio core tries to power-up internally, and this kicks off the codec runtime PM code that tries to take the same coef_mutex. In order to avoid the deadlock, do the temporary power up/down around the coef_mutex acquisition and release. This assures that the power-up sequence runs before the mutex, hence no re-entrance will happen. Fixes: b837a9f5ab3b ("ALSA: hda: realtek: Fix race at concurrent COEF updates") Reported-and-tested-by: Julian Wollrath <jwollrath@web.de> Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20220214132838.4db10fca@schienar Link: https://lore.kernel.org/r/20220214130410.21230-1-tiwai@suse.de Signed-off-by: Takashi Iwai <tiwai@suse.de>
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.
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