> Takashi: > > > Thank you for your quick response. Unfortunately I've already tried > all of the other volume controls, including headphone and surround, > and nothing worked. I'm going to continue looking at the chip/driver > and see what I can come up with, but at least you've given me a > direction to look. Thanks! > > > Takashi Iwai wrote: > > > > there is also "master" control on this chip, and this control should > > work. on many mobos, the true line-out (aka headphone) pin is > > connected to the line-out jack. in such a case, ac97 master control > > doesn't do anything but other control such as "headphone" or > > "surround" might affect the volume. > > > > > > anyway, there must be some way to control the "master" volume, in > > addition to "pcm" switch. > > if not, it should be a bug of the driver, or the chip is messy and we > > need a workaround. > > > > > > > > Takashi
Steven and Takashi, During the past few months many have complained about the problems with the Master and PCM volume controls not working with the CMI9739 AC97 codec. In my case I have a MB with a VIA VT8237 and a CMEDIA CMI9739. When using the ALSA mixer the PCM volume control is disabled (you can only mute/unmute PCM) and the master volume control does not work - the sound out of the speakers is muted with the master volume at 0% and at full volume otherwise regardless of setting. Takashi and others have pointed out that the CMI9739 does not provide PCM Volume control. Although this is correct please note that both the Windows driver as well as the CMEDIA Linux driver (available at www.cmedia.com.tw) provide fully operational volume controls for both Master and PCM volumes. I also downloaded the VIA Linux driver for the VT8237 (available from the VIA website). Unlike the very basic CMEDIA driver, the VIA driver is "full featured" and interestingly enough has the same problems with the volume control as the ALSA driver. This leads me to believe that the problem is with the ALSA ac97_codec driver which is used by the VIA driver and not with the snd-via82xx driver. Steven, note that the CMEDIA driver, although basic and not based on ALSA, works just fine (both volume controls work). You may want to consider using it until the ALSA driver is fixed. Since the source code for the CMEDIA driver is available (unlike the VIA driver) I have been trying to figure out how they implemented the volume controls. Unfortunately I am not familiar enough with linux sound to really make much sense of the code (and the ALSA documentation is a bit skimpy). I have written a small perl program that displays register value changes (from /proc/asound/card0/ac97#0regs) to see if I can spot the problem with the ALSA driver. I was hoping to compare them to the register values set by the CMEDIA driver, but this driver does not use the /proc interface. (Perhaps someone with the right knowledge can modify the CMEDIA driver to write register values to /proc like the ALSA driver does.) Takashi, do you know if there is some other way to display the register values used by the CMEDIA driver? Alternatively, do you know how to configure the ASLA driver so that at least the master volume control works? Or, is there some data I can capture to help the alsa developers debug this problem? Jose By the way, The CMEDIA driver is at http://www.cmedia.com.tw/driver/Linux/Ac97/cmaudio-041.tar.gz The specification sheet for the 9739 is at http://www.cmedia.com.tw/e_tech_01.htm The VIA driver is available at http://www.viaarena.com/?PageID=2 ------------------------------------------------------- This SF.Net email sponsored by: ApacheCon 2003, 16-19 November in Las Vegas. Learn firsthand the latest developments in Apache, PHP, Perl, XML, Java, MySQL, WebDAV, and more! http://www.apachecon.com/ _______________________________________________ Alsa-user mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/alsa-user
