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ALSA: hda - Update documentation

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Update documentation regarding codec probing; the new probe_only option
and the new probe_mask usage.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2009-02-13 08:33:55 +01:00
parent 20db7cb0ac
commit ae374d667a
2 changed files with 20 additions and 0 deletions
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3
Documentation/sound/alsa/ALSA-Configuration.txt
View File

@ -757,6 +757,9 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed.
model - force the model name
position_fix - Fix DMA pointer (0 = auto, 1 = use LPIB, 2 = POSBUF)
probe_mask - Bitmask to probe codecs (default = -1, meaning all slots)
When the bit 8 (0x100) is set, the lower 8 bits are used
as the "fixed" codec slots; i.e. the driver probes the
slots regardless what hardware reports back
probe_only - Only probing and no codec initialization (default=off);
Useful to check the initial codec status for debugging
bdl_pos_adj - Specifies the DMA IRQ timing delay in samples.

17
Documentation/sound/alsa/HD-Audio.txt
View File

@ -109,6 +109,13 @@ slot, pass `probe_mask=1`. For the first and the third slots, pass
Since 2.6.29 kernel, the driver has a more robust probing method, so
this error might happen rarely, though.
On a machine with a broken BIOS, sometimes you need to force the
driver to probe the codec slots the hardware doesn't report for use.
In such a case, turn the bit 8 (0x100) of `probe_mask` option on.
Then the rest 8 bits are passed as the codec slots to probe
unconditionally. For example, `probe_mask=0x103` will force to probe
the codec slots 0 and 1 no matter what the hardware reports.
Interrupt Handling
~~~~~~~~~~~~~~~~~~
@ -461,6 +468,16 @@ run with `--no-upload` option, and attach the generated file.
There are some other useful options. See `--help` option output for
details.
When a probe error occurs or when the driver obviously assigns a
mismatched model, it'd be helpful to load the driver with
`probe_only=1` option (at best after the cold reboot) and run
alsa-info at this state. With this option, the driver won't configure
the mixer and PCM but just tries to probe the codec slot. After
probing, the proc file is available, so you can get the raw codec
information before modified by the driver. Of course, the driver
isn't usable with `probe_only=1`. But you can continue the
configuration via hwdep sysfs file if hda-reconfig option is enabled.
hda-verb
~~~~~~~~