HDA-VERB -- Send a HD-audio command

hda-verb is a small program to send HD-audio commands to the given
ALSA hwdep device on the hd-audio interface.

First off, build HD-audio driver with hwdep support.  For the kernel
config, set CONFIG_SND_HDA_HWDEP=y.  When you build ALSA drivers from
alsa-driver tarball, usually this is set automatically.

Once snd-hda-intel driver is built with the hwdep support, you should
have a hwdep device such as /dev/snd/hwC0D0.

The program takes four arguments, the hwdep device name, the widget NID,
the verb and the parameter.  For example,

	% hda-verb /dev/snd/hwC0D0 0x12 0x701 2

The verb argument can be a string like "PARAMETERS".  Also the
parameter argument can be a string like "VENDOR_ID" as well.

	% hda-verb /dev/snd/hwC0D0 0x0 PARAMETERS VENDOR_ID

The string is case insensitive.  Also, it doesn't have to be the full
string but only has to be unique.  E.g. "par" is enough to mean
"PARAMETER", and "set_a" is enough as "SET_AMP_GAIN_MUTE".

	% hda-verb /dev/snd/hwC0D0 2 set_a 0xb080

The program executs the given verb, shows the result and quits.
Usually you need to be root to run this command.

Use this program carefully.  Sending an invalid verb may screw up the
codec communication, which requires either a reboot or reloading of
the sound driver eventually.