At Tue, 5 Sep 2006 20:24:55 +0100, Jochen Voss wrote: > > Hello Takashi, > > I do not completely understand the suggested test, do I just blindly > follow your suggestions. I am sorry about the absence of more > intelligent contributions from my side here. > > On Tue, Sep 05, 2006 at 11:36:50AM +0200, Takashi Iwai wrote: > > > I tried the following. My amixer output is at the end of the mail for > > > reference. first I created two shell scripts: > > > > > > -- s1.sh ------------------------------------------------------------- > > > #! /bin/sh > > > amixer set "PCM Capture Gain" 2 > > > amixer set "PCM Capture Gain" 0 > > > amixer set "PCM" 0 > > > amixer set "PCM" 80% > > > ---------------------------------------------------------------------- > > > > > > -- s2.sh ------------------------------------------------------------- > > > #! /bin/sh > > > amixer set "PCM Capture Gain" 0 > > > amixer set "PCM Capture Gain" 2 > > > amixer set "PCM" 0 > > > amixer set "PCM" 80% > > > ---------------------------------------------------------------------- > > > > > > and then I run the following command on the shell > > > > > > while true; do ./s1.sh; sleep 1; ./s2.sh; sleep 1; done > > > > > > While this was running I recorded a wav file with arecord. The volume > > > of the recorded file was extremely low (is this normal?) so I > > > normalised it with audacity. I looked at the wave form in audacity > > > and I played the normalised file with alsamixer. > > > > In s2.sh, use a higher value for "PCM Capture Gain", such as 20. > > If the volume is still low, then IPGA is not independent. > > I used 'amixer set "PCM Capture Gain" 20' now in s2.sh only. Was this > the plan? Result: there is now an audible crack when s2.sh is > executed, but the volume before and after the cracks still seems to be > the same. The crack doesn't matter seriously, but just the volume. > I also tried something else: when I alternate between > ---------------------------------------------------------------------- > amixer set "PCM Capture Gain" 0 > amixer set "PCM Capture Gain" 20 > amixer set "PCM" 0 > amixer set "PCM" 80% > ---------------------------------------------------------------------- > and > ---------------------------------------------------------------------- > amixer set "PCM" 0 > amixer set "PCM" 80% > amixer set "PCM Capture Gain" 0 > amixer set "PCM Capture Gain" 20 > ---------------------------------------------------------------------- > the recording has alternating load and quiete stretches. Whatever this > might tell us about the ADC, it looks like a bug to me: the order of > setting the two controls shouldn't matter. Or am I confused again? Well, assume that "PCM Capture" and "PCM Capture Gain" are independent. If so, the above two should result in the same state. If it's not independent but the register 4 & 5 take single values (that was the behavior of your original implementation), the above two cases must make a clear difference: in the former case, the gain is below 0dB, and in the latter it's +10dB. Was it so through your tests? Also, it's possible that I did make a silly mistake. Put a debug printk around ak->ops.write() in snd_akm4xxx_write() to check what values are written to register 4 and 5. Takashi ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-devel
