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The FPGA access through the GPIO port does not interfere with other sound processor register access, so there is no need to subject it to emu_lock. And after moving all FPGA access out of the interrupt handler, it does not need to be IRQ-safe, either. What's more, attaching the dock causes a firmware upload, which takes several seconds. We really don't want to disable IRQs for this long, and even less also have someone else spin with IRQs disabled waiting for us. Therefore, use a mutex for FPGA access locking. This makes the code somewhat more noisy, as we need to wrap bigger sections into the mutex, as it needs to enclose the spinlocks. The latter has the "side effect" of fixing dock FPGA programming in a corner case: a really badly timed mixer access right between entering FPGA programming mode and uploading the netlist would mess up the protocol. Signed-off-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de> Signed-off-by: Takashi Iwai <tiwai@suse.de> Message-ID: <20240428093716.3198666-5-oswald.buddenhagen@gmx.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 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.