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[ Upstream commit 5aedb8d8336b0a0421b58ca27d1b572aa6695b5b ] The existing code enables the Cadence IP interrupts after the bus reset sequence. The problem with this sequence is that it might be pre-empted, giving SoundWire devices time to sync and report as ATTACHED before the interrupts are enabled. In that case, the Cadence IP will not detect a state change and will not throw an interrupt to proceed with the enumeration of a Device0. In our overnight stress tests, we observed that a slight sub-millisecond delay in enabling interrupts after the reset was correlated with detection failures. This problem is more prevalent on the LunarLake silicon, likely due to SOC integration changes, but it was observed on earlier generations as well. This patch reverts the sequence, with the interrupts enabled before performing the bus reset. This removes the race condition and makes sure the Cadence IP is able to detect the presence of a Device0 in all cases. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com> Link: https://lore.kernel.org/r/20240805115003.88035-1-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.