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[ Upstream commit0a0d1740bd] The existing code copies the hw_params pointer and reuses it later in .prepare, specifically to re-initialize the ALH DMA channel information that's lost in suspend-resume cycles. This is not needed, we can directly access the information from the substream/rtd - as done for the HDAudio DAIs in sound/soc/sof/intel/hda-dai.c In addition, using the saved pointer causes the suspend-resume test cases to fail on specific platforms, depending on which version of GCC is used. Péter Ujfalusi and I have spent long hours to root-cause this problem that was reported by the Intel CI first with 6.2-rc1 and again v6.3-rc1. In the latter case we were lucky that the problem was 100% reproducible on local test devices, and found out that adding a dev_dbg() or adding a call to usleep_range() just before accessing the saved pointer "fixed" the issue. With errors appearing just by changing the compiler version or minor changes in the code generated, clearly we have a memory management Heisenbug. The root-cause seems to be that the hw_params pointer is not persistent. The soc-pcm code allocates the hw_params structure on the stack, and passes it to the BE dailink hw_params and DAIs hw_params. Saving such a pointer and reusing it later during the .prepare stage cannot possibly work reliably, it's broken-by-design since v5.10. It's astonishing that the problem was not seen earlier. This simple fix will have to be back-ported to -stable, due to changes to avoid the use of the get/set_dmadata routines this patch will only apply on kernels older than v6.1. Fixes:a5a0239c27("soundwire: intel: reinitialize IP+DSP in .prepare(), but only when resuming") Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com> Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com> Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com> Link: https://lore.kernel.org/r/20230321022642.1426611-1-yung-chuan.liao@linux.intel.com Signed-off-by: Vinod Koul <vkoul@kernel.org> Signed-off-by: Sasha Levin <sashal@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.