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Diffstat (limited to 'Documentation/sound/kernel-api/writing-an-alsa-driver.rst')
| -rw-r--r-- | Documentation/sound/kernel-api/writing-an-alsa-driver.rst | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/Documentation/sound/kernel-api/writing-an-alsa-driver.rst b/Documentation/sound/kernel-api/writing-an-alsa-driver.rst index e6365836fa8b..01d59b8aea92 100644 --- a/Documentation/sound/kernel-api/writing-an-alsa-driver.rst +++ b/Documentation/sound/kernel-api/writing-an-alsa-driver.rst @@ -3508,14 +3508,15 @@ field must be set, though). “IEC958 Playback Con Mask” is used to return the bit-mask for the IEC958 status bits of consumer mode. Similarly, “IEC958 Playback Pro Mask” -returns the bitmask for professional mode. They are read-only controls, -and are defined as MIXER controls (iface = -``SNDRV_CTL_ELEM_IFACE_MIXER``). +returns the bitmask for professional mode. They are read-only controls. Meanwhile, “IEC958 Playback Default” control is defined for getting and -setting the current default IEC958 bits. Note that this one is usually -defined as a PCM control (iface = ``SNDRV_CTL_ELEM_IFACE_PCM``), -although in some places it's defined as a MIXER control. +setting the current default IEC958 bits. + +Due to historical reasons, both variants of the Playback Mask and the +Playback Default controls can be implemented on either a +``SNDRV_CTL_ELEM_IFACE_PCM`` or a ``SNDRV_CTL_ELEM_IFACE_MIXER`` iface. +Drivers should expose the mask and default on the same iface though. In addition, you can define the control switches to enable/disable or to set the raw bit mode. The implementation will depend on the chip, but |