2d9ea39917
We've had an x86-specific SG-buffer handling code, but now it can be merged gracefully with the standard non-contiguous DMA pages. After the migration, SNDRV_DMA_TYPE_DMA_SG becomes identical with SNDRV_DMA_TYPE_NONCONTIG on x86, while others still fall back to SNDRV_DMA_TYPE_DEV. The remaining problem is about the SG-buffer with WC pages: the DMA core stuff on x86 doesn't treat it well, so we still need some special handling to manipulate the page attribute manually. The mmap handler for SNDRV_DMA_TYPE_DEV_SG_WC still returns -ENOENT intentionally for the fallback to the default handler. Link: https://lore.kernel.org/r/20211017074859.24112-4-tiwai@suse.de 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.
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.