mainlining shenanigans
ade49db337
AMD/ATI and Nvidia HDMI codec drivers didn't have the audio component binding like i915, but it worked only with the traditional HD-audio unsolicited event for the HDMI hotplug detection and the ELD read-up thereafter. This has been a problem in many ways: first of all, it goes through the hardware event transition (from GPU register write, HD-audio controller trigger, and finally to HD-audio unsolicited event handling), which is often unreliable and may miss some opportunities. Second, each unsol event handling and ELD read-up need the explicit power up / down when the codec is in the runtime suspend. Last but not least, which is the most important, the hotplug wakeup may be missed when the HD-audio controller is in runtime suspend. Especially the last point is a big problem due to the recent change relevant with vga_switcheroo that forcibly enables the runtime PM for AMD HDMI controllers. These issues are solved by introducing the audio component; the hotplug notification is done by a direct function callback, which is more accurate and reliable, and it can be processed without the actual hardware access, i.e. no runtime PM trigger is needed, and the HD-audio gets the event even if it's in runtime suspend. The same for ELD query, as it's read directly from the cached ELD bytes stored in the DRM driver, hence the whole hardware access can be skipped. So here it is: this patch implements the audio component binding with AMD/ATI and Nouveau DRM drivers. The biggest difference from i915 implementation is that this binding is fully optional and it can be enabled asynchronously on the fly. That is, the driver will switch from the HD-audio unsolicited event to the notify callback once when the DRM component gets bound. Similarly, when DRM driver gets unloaded, the HDMI event handling returns to the legacy mode, too. Also, another difference from i915 is that the new code registers the component in the codec driver, while i915 HDMI codec assumes the component binding was already done in the HD-audio controller driver. Hence the new code does need to de-register the component binding at the codec exit, too. Some other details: - The match component ops assumes that both VGA and HD-audio controller PCI entries belong to the same PCI bus, and only accepts such an entry. - The pin2port audio_ops is implemented with assumption of the fixed widget layout. For AMD, it's starting from 3, with step 2 (3, 5, 7, ...), while for Nvidia, it's starting from 4, with step 1 (4, 5, 6, ...) As of this patch, the corresponding component isn't implemented in DRM side, so this change alone won't give any benefit. By the following changes in DRM sides, the mission will be completed. Signed-off-by: Takashi Iwai <tiwai@suse.de> |
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| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| 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 | ||
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.