a4965d98b4
The "comedi_isadma" module calls `dma_alloc_coherent()` and `dma_free_coherent()` with a NULL device pointer which is no longer allowed. If the `hw_dev` member of the `struct comedi_device` has been set to a valid device, that can be used instead. Unfortunately, all the current users of the "comedi_isadma" module leave the `hw_dev` member set to NULL. In that case, fall back to using the comedi "class" device pointed to by the `class_dev` member if that is non-NULL. In that case, make it "DMA-capable" with a coherent DMA mask set to the ISA bus limit of 16MB (24 bits). Signed-off-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.