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cbea6e5a77
Currently we check only the substream->dma_buffer as the preset of the buffer configuration for verifying the availability of mmap. But a few drivers rather set up the buffer in the own way without the standard buffer preallocation using substream->dma_buffer, and they miss the proper checks. (Now it's working more or less fine as most of them are running only on x86). Actually, they may set up the runtime dma_buffer (referred via snd_pcm_get_dma_buf()) at the open callback, though. That is, this could have been used as the primary source. This patch changes the hw_support_mmap() function to check the runtime dma buffer at first. It's usually NULL with the standard buffer preallocation, and in that case, we continue checking substream->dma_buffer as fallback. Link: https://lore.kernel.org/r/20210809071829.22238-2-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.