From: Wu Fengguang <fengguang.wu@intel.com>
To: Takashi Iwai <tiwai@suse.de>
Cc: "alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>
Subject: Re: PROC_COEF/PROC_INDEX question
Date: Fri, 7 Aug 2009 18:12:12 +0800 [thread overview]
Message-ID: <20090807101212.GA5825@localhost> (raw)
In-Reply-To: <s5hfxc4ym5t.wl%tiwai@suse.de>
On Fri, Aug 07, 2009 at 06:05:02PM +0800, Takashi Iwai wrote:
> At Fri, 7 Aug 2009 18:01:21 +0800,
> Wu Fengguang wrote:
> >
> > On Fri, Aug 07, 2009 at 05:45:14PM +0800, Takashi Iwai wrote:
> > > At Fri, 7 Aug 2009 17:38:59 +0800,
> > > Wu Fengguang wrote:
> > > >
> > > > Hello,
> > > >
> > > > I'm not sure of the usage for GET_PROC_COEF/GET_COEF_INDEX, and found
> > > > that their return value is unstable (changing all the time) for codec:
> > > >
> > > > Codec: Realtek ALC888
> > > > Address: 2
> > > > Function Id: 0x1
> > > > Vendor Id: 0x10ec0888
> > > > Subsystem Id: 0x80860023
> > > > Revision Id: 0x100202
> > > >
> > > > For example:
> > > >
> > > > # hda-verb /dev/snd/hwC0D2 0x20 GET_PROC_COEF 0
> > > > nid = 0x20, verb = 0xc00, param = 0x0
> > > > value = 0x80
> > > > # hda-verb /dev/snd/hwC0D2 0x20 GET_COEF_INDEX 0
> > > > nid = 0x20, verb = 0xd00, param = 0x0
> > > > value = 0xe
> > > > # hda-verb /dev/snd/hwC0D2 0x20 GET_PROC_COEF 0
> > > > nid = 0x20, verb = 0xc00, param = 0x0
> > > > value = 0x9c00
> > > > # hda-verb /dev/snd/hwC0D2 0x20 GET_COEF_INDEX 0
> > > > nid = 0x20, verb = 0xd00, param = 0x0
> > > > value = 0xf
> > > >
> > > > I wonder if this is the normal case?
> > >
> > > AFAIK, depending on the mode, the index is incremented automatically.
> >
> > Ah, yes. That's in line with the above data.
> >
> > When repeatingly call GET_PROC_COEF, it returns some 'random' values:
> >
> > # hda-verb /dev/snd/hwC0D2 0x20 GET_PROC_COEF 0
> > nid = 0x20, verb = 0xc00, param = 0x0
> > value = 0x4f
> > # hda-verb /dev/snd/hwC0D2 0x20 GET_PROC_COEF 0
> > nid = 0x20, verb = 0xc00, param = 0x0
> > value = 0x8000
> > # hda-verb /dev/snd/hwC0D2 0x20 GET_PROC_COEF 0
> > nid = 0x20, verb = 0xc00, param = 0x0
> > value = 0x2520
> > # hda-verb /dev/snd/hwC0D2 0x20 GET_PROC_COEF 0
> > nid = 0x20, verb = 0xc00, param = 0x0
> > value = 0x3e00
>
> I guess it's not random but just the value of the next index.
>
> > But when repeatingly call GET_COEF_INDEX, it returns the same value:
> >
> > # hda-verb /dev/snd/hwC0D2 0x20 GET_COEF_INDEX 0
> > nid = 0x20, verb = 0xd00, param = 0x0
> > value = 0xd
> > # hda-verb /dev/snd/hwC0D2 0x20 GET_COEF_INDEX 0
> > nid = 0x20, verb = 0xd00, param = 0x0
> > value = 0xd
>
> Reading the index itself doesn't increment the index. Reading
> the coef value increases the index. So is my understanding.
OK, so the coef read has some 'side effects', hehe.
prev parent reply other threads:[~2009-08-07 10:12 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-08-07 9:38 PROC_COEF/PROC_INDEX question Wu Fengguang
2009-08-07 9:45 ` Takashi Iwai
2009-08-07 10:01 ` Wu Fengguang
2009-08-07 10:05 ` Takashi Iwai
2009-08-07 10:12 ` Wu Fengguang [this message]
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