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The IDA-based allocation is useful to simplify debug, but it was also introduced as a prerequisite to deal with the Intel Lunar Lake hardware programming sequences: the wake-ups have to be handled with a system-unique SDI address at the HDaudio controller level. At the time, the restriction introduced by the IDA to 8 devices total seemed perfectly fine, but recently hardware vendors created configurations with more than 8 devices. Add a new allocation strategy to allow for more than 8 devices using information on the type of devices, and only use the IDA-based allocation for devices capable of generating a wake. In theory the information on wake capabilities should come from firmware, but none of the existing ACPI tables provide it. The drivers set the 'wake_capable' property, but this cannot be used reliably: if the driver probe happens *after* the enumeration, then that property is not initialized yet. Trying to modify the device_number on-the-fly proved to be an impossible task generating race conditions left and right. The only reliable work-around to control the enumeration is to add a quirk table. It's ugly but until platform firmware improves, hopefully as a result of MIPI/SDCA stardization, we can expect that quirk table to grow for each new headset or microphone codec. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> Reviewed-by: Rander Wang <rander.wang@intel.com> Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com> Link: https://lore.kernel.org/r/20230731091333.3593132-4-yung-chuan.liao@linux.intel.com Signed-off-by: Vinod Koul <vkoul@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.