diff options
Diffstat (limited to 'Documentation/sound')
| -rw-r--r-- | Documentation/sound/alsa-configuration.rst | 34 | ||||
| -rw-r--r-- | Documentation/sound/hd-audio/notes.rst | 11 | ||||
| -rw-r--r-- | Documentation/sound/kernel-api/writing-an-alsa-driver.rst | 33 |
3 files changed, 76 insertions, 2 deletions
diff --git a/Documentation/sound/alsa-configuration.rst b/Documentation/sound/alsa-configuration.rst index b36af65a08ed..65f61695f561 100644 --- a/Documentation/sound/alsa-configuration.rst +++ b/Documentation/sound/alsa-configuration.rst @@ -1059,6 +1059,12 @@ The model name ``generic`` is treated as a special case. When this model is given, the driver uses the generic codec parser without "codec-patch". It's sometimes good for testing and debugging. +The model option can be used also for aliasing to another PCI or codec +SSID. When it's passed in the form of ``model=XXXX:YYYY`` where XXXX +and YYYY are the sub-vendor and sub-device IDs in hex numbers, +respectively, the driver will refer to that SSID as a reference to the +quirk table. + If the default configuration doesn't work and one of the above matches with your device, report it together with alsa-info.sh output (with ``--no-upload`` option) to kernel bugzilla or alsa-devel @@ -2252,6 +2258,27 @@ delayed_register The driver prints a message like "Found post-registration device assignment: 1234abcd:04" for such a device, so that user can notice the need. +quirk_flags + Contains the bit flags for various device specific workarounds. + Applied to the corresponding card index. + + * bit 0: Skip reading sample rate for devices + * bit 1: Create Media Controller API entries + * bit 2: Allow alignment on audio sub-slot at transfer + * bit 3: Add length specifier to transfers + * bit 4: Start playback stream at first in implement feedback mode + * bit 5: Skip clock selector setup + * bit 6: Ignore errors from clock source search + * bit 7: Indicates ITF-USB DSD based DACs + * bit 8: Add a delay of 20ms at each control message handling + * bit 9: Add a delay of 1-2ms at each control message handling + * bit 10: Add a delay of 5-6ms at each control message handling + * bit 11: Add a delay of 50ms at each interface setup + * bit 12: Perform sample rate validations at probe + * bit 13: Disable runtime PM autosuspend + * bit 14: Ignore errors for mixer access + * bit 15: Support generic DSD raw U32_BE format + * bit 16: Set up the interface at first like UAC1 This module supports multiple devices, autoprobe and hotplugging. @@ -2261,11 +2288,14 @@ check. NB: ``ignore_ctl_error=1`` may help when you get an error at accessing the mixer element such as URB error -22. This happens on some -buggy USB device or the controller. +buggy USB device or the controller. This workaround corresponds to +the ``quirk_flags`` bit 14, too. -NB: quirk_alias option is provided only for testing / development. +NB: ``quirk_alias`` option is provided only for testing / development. If you want to have a proper support, contact to upstream for adding the matching quirk in the driver code statically. +Ditto for ``quirk_flags``. If a device is known to require specific +workarounds, please report to the upstream. Module snd-usb-caiaq -------------------- diff --git a/Documentation/sound/hd-audio/notes.rst b/Documentation/sound/hd-audio/notes.rst index cf4d7158af78..d118b6fe269b 100644 --- a/Documentation/sound/hd-audio/notes.rst +++ b/Documentation/sound/hd-audio/notes.rst @@ -215,6 +215,17 @@ There are a few special model option values: * when ``generic`` is passed, the codec-specific parser is skipped and only the generic parser is used. +A new style for the model option that was introduced since 5.15 kernel +is to pass the PCI or codec SSID in the form of ``model=XXXX:YYYY`` +where XXXX and YYYY are the sub-vendor and sub-device IDs in hex +numbers, respectively. This is a kind of aliasing to another device; +when this form is given, the driver will refer to that SSID as a +reference to the quirk table. It'd be useful especially when the +target quirk isn't listed in the model table. For example, passing +model=103c:8862 will apply the quirk for HP ProBook 445 G8 (which +isn't found in the model table as of writing) as long as the device is +handled equivalently by the same driver. + Speaker and Headphone Output ---------------------------- diff --git a/Documentation/sound/kernel-api/writing-an-alsa-driver.rst b/Documentation/sound/kernel-api/writing-an-alsa-driver.rst index 6da9c887a48b..176b73583b7a 100644 --- a/Documentation/sound/kernel-api/writing-an-alsa-driver.rst +++ b/Documentation/sound/kernel-api/writing-an-alsa-driver.rst @@ -4172,6 +4172,39 @@ module license as GPL, etc., otherwise the system is shown as “tainted”. MODULE_LICENSE("GPL"); +Device-Managed Resources +======================== + +In the examples above, all resources are allocated and released +manually. But human beings are lazy in nature, especially developers +are lazier. So there are some ways to automate the release part; it's +the (device-)managed resources aka devres or devm family. For +example, an object allocated via :c:func:`devm_kmalloc()` will be +freed automatically at unbinding the device. + +ALSA core provides also the device-managed helper, namely, +:c:func:`snd_devm_card_new()` for creating a card object. +Call this functions instead of the normal :c:func:`snd_card_new()`, +and you can forget the explicit :c:func:`snd_card_free()` call, as +it's called automagically at error and removal paths. + +One caveat is that the call of :c:func:`snd_card_free()` would be put +at the beginning of the call chain only after you call +:c:func:`snd_card_register()`. + +Also, the ``private_free`` callback is always called at the card free, +so be careful to put the hardware clean-up procedure in +``private_free`` callback. It might be called even before you +actually set up at an earlier error path. For avoiding such an +invalid initialization, you can set ``private_free`` callback after +:c:func:`snd_card_register()` call succeeds. + +Another thing to be remarked is that you should use device-managed +helpers for each component as much as possible once when you manage +the card in that way. Mixing up with the normal and the managed +resources may screw up the release order. + + How To Put Your Driver Into ALSA Tree ===================================== |