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Linux kernel source tree
4bd1adb85a
The existing NOCODEC mode enforces a build-time mutual exclusion with the HDaudio link support, mostly to avoid any dependency on the snd_hdac library and references to HDAudio codec/i915 stuff. This is very useful to track dependencies and test a minimal configuration, but very painful for developers and CI: a recompilation and reinstall of the kernel modules is required. This patch suggests an alternate middle ground where the selection of the machine driver and all codec-related actions are bypassed at run-time, contingent on a kernel module parameter being set. For example setting BIT(10) with 'options snd_sof sof_debug=0x401' is enough to switch from an HDaudio card to a nocodec one. This new DEBUG_NOCODEC mode is not suitable for distributions and end-users. It's not even recommended on all platforms, i.e. the NOCODEC mode is known not to work on specific devices where the BIOS did not configure support for I2S/DMIC interfaces. The usual development devices such as Chromebooks, Up boards and Intel RVP are the only recommended platforms where this mode can be supported. Note that the dynamic switch between HDaudio and nocodec may not always possible depending on hardware layout, pin-mux options, and BIOS settings. The audio subsustems on Intel platforms has to support 4 types of interfaces and pin-mux can be complicated. Reviewers might ask: why didn't we do this earlier? The main reason is that all the codec-related configurations were not cleanly separated out in the sof/intel directory. With all the cleanups done recently, adding this opt-in behavior is relatively straightforward. Tested on UpExtreme (WHL) and UpExtreme i11 (TGL). Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> Reviewed-by: Rander Wang <rander.wang@intel.com> Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com> Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com> Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com> Link: https://lore.kernel.org/r/20221027193540.259520-22-pierre-louis.bossart@linux.intel.com Signed-off-by: Mark Brown <broonie@kernel.org> |
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| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| 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.