42e748a0b3
In some cases (mainly for x86), we need the DMA coherent buffer with non-cached pages. Although this has been done in each driver side like HD-audio and intel8x0, it can be done cleaner in the core memory allocator. This patch adds the new types, SNDRV_DMA_TYPE_DEV_UC and SNDRV_DMA_TYPE_DEV_UC_SG, for allocating such non-cached buffer pages. On non-x86 architectures, they work as same as the standard SNDRV_DMA_TYPE_DEV and *_SG. One additional change by this move is that we can assure to pass the non-cached pgprot to the vmapped buffer, too. It eventually fixes the case like non-snoop mode without mmap access on HD-audio. Signed-off-by: Takashi Iwai <tiwai@suse.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 Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
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.