c31427d0d2
Like many other drivers, HD-audio drivers also do PCM buffer preallocation to assure the buffer pages allocated at the early boot stage. This step is useful for platforms that may fail to allocate the PCM hardware buffers -- which is mostly for either large continuous pages or with the specific DMA mask (like emu10k1). OTOH, when a buffer is allocated as SG-buffer and the DMA mask is either 32 or 64 bits, the allocation almost never fails unless it hits the real OOM situation. In such a case, we don't need the preallocation inevitably unlike the cases above. That said, we may drop the preallocation for HD-audio that does allocate via SG-buffers, and the patch achieves it. However, there is one caveat: the buffer allocation behavior depends on CONFIG_SND_DMA_SGBUF, and it falls back to the continuous pages when it's not set. And, currently this SG buffer allocation is enabled only on x86 platforms. So, covering those fall-outs, the patch adjusts CONFIG_SND_HDA_PREALLOC_SIZE depending on the condition, and keeps the old behavior as-is for non-x86 platforms. On x86, the kconfig item is no longer adjustable but always set to zero for disabling the preallocation. You can still enable the preallocation via procfs interface at any time later, too. Link: https://lore.kernel.org/r/20200120124423.11862-2-tiwai@suse.de Signed-off-by: Takashi Iwai <tiwai@suse.de> |
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| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
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.