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Date: Thu, 12 Jun 2008 15:58:30 +0100 From: "Daniel J Blueman" <daniel.blueman@...il.com> To: "Takashi Iwai" <tiwai@...e.de> Cc: "Vegard Nossum" <vegard.nossum@...il.com>, "Linux Kernel" <linux-kernel@...r.kernel.org> Subject: Re: ALC883 recording troubles... On Thu, Jun 12, 2008 at 3:23 PM, Takashi Iwai <tiwai@...e.de> wrote: > At Thu, 12 Jun 2008 16:18:14 +0200, > Vegard Nossum wrote: >> >> On Thu, Jun 12, 2008 at 4:02 PM, Takashi Iwai <tiwai@...e.de> wrote: >> > At Thu, 12 Jun 2008 15:55:45 +0200, >> > Vegard Nossum wrote: >> >> >> >> On Thu, Jun 12, 2008 at 3:52 PM, Takashi Iwai <tiwai@...e.de> wrote: >> >> > At Thu, 12 Jun 2008 15:48:32 +0200, >> >> > Vegard Nossum wrote: >> >> >> >> >> >> The external mic: >> >> >> >> >> >> Node 0x18 [Pin Complex] wcaps 0x40018f: Stereo Amp-In Amp-Out >> >> >> Amp-In caps: ofs=0x00, nsteps=0x02, stepsize=0x4f, mute=0 >> >> >> Amp-In vals: [0x00 0x00] >> >> > >> >> > The input volume is zero. Try to raise "Mic Boost" (if present)? >> >> >> >> They're already all up. >> >> >> >> Line In Boost = 100 >> >> Mic Boost = 100 >> >> Internal Mic Boost = 100 >> >> >> >> Right after changing all these to max, I've read the value from >> >> card0/codec#0 again: >> >> >> >> Node 0x18 [Pin Complex] wcaps 0x40018f: Stereo Amp-In Amp-Out >> >> Amp-In caps: ofs=0x00, nsteps=0x02, stepsize=0x4f, mute=0 >> >> Amp-In vals: [0x00 0x00] >> >> >> >> There doesn't seem to be any difference. Even when changing them all >> >> to 0 in alsamixer, this output stays the same. >> > >> > Weird. What happens if you execute the verb directly via hda-verb >> > program like below? >> > hda-verb /dev/snd/hwC0D0 0x18 SET_AMP 0x7002 >> > >> >> Yep, this has the same effect has changing the "Mic Boost" control in >> the Playback section of alsamixer. >> >> What I discovered now, though, is that I get a much wider range of >> values from the external mic (so playback of the captured data >> actually sounds correct). It actually works, but there is still a very >> strong DC offset that seems dependent on the level of the "Capture" >> control. This offset still makes it unusable for recording, since even >> slightly louder noises will clip the samples. >> >> It also seems that this control is reset each time I start Audacity >> (even though the "Mic boost" level in alsamixer doesn't change). But I >> guess this unrelated to the DC offset issue. >> >> Changing the voltage level now (0x21, 0x22, 0x24, with Mic Boost at >> 0x02) doesn't change the DC offset, but has the same effect as before >> (the values fluctuate, but eventually stabilize at the same level). > > Hmm, then it's all what I can guess right now. > There might be some vendor-specific settings I don't know of. Maybe. I can readily dump the PCI config space of the Intel HD-audio controller in Windows and list differences; the datasheet from Intel allows us to decode the registers. Will this help us any? Of course, we really need to dump the target behind the HD-bus, but that's another matter... > To be sure, try the following git tree (master branch), pull on > 2.6.26: > > git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6.git > > This contains the patches for the next kernel, and some of them are > related with Realtek codecs. > > > Takashi > -- Daniel J Blueman -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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