From ae374d667a54fb5e2c9c0c4e87b206bd665f3ad6 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Fri, 13 Feb 2009 08:33:55 +0100 Subject: ALSA: hda - Update documentation Update documentation regarding codec probing; the new probe_only option and the new probe_mask usage. Signed-off-by: Takashi Iwai --- Documentation/sound/alsa/HD-Audio.txt | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'Documentation/sound/alsa/HD-Audio.txt') diff --git a/Documentation/sound/alsa/HD-Audio.txt b/Documentation/sound/alsa/HD-Audio.txt index 8d68fff71839..99f7fbbe3e67 100644 --- a/Documentation/sound/alsa/HD-Audio.txt +++ b/Documentation/sound/alsa/HD-Audio.txt @@ -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 ~~~~~~~~ -- cgit v1.2.3