I think I have found what is causing this problem: in ac97_patch.c / int patch_vt1617a(...) there is a line of code: >>> snd_ac97_write_cache(a97, 0x5c, 0x20); According to a comment, this code is supposed to "bring the analog power consumption to normal, like WinXP driver for EPIA SP". If I comment out this line, the problem appears to be solved ... I can now put all volume controls to maximum values and the sound will keep playing. This is consistent with the apparent introduction of this bug in kernel 2.6.19 (includes alsa-driver version 1.0.12rc1): no such problem occurred until 2.6.18, but all kernels since 2.6.19 do suffer from this problem. The line of code above first shows up in linux-2.6.19. Unfortunately, since I do not have a datasheet for the VT1617A chip set, I cannot verify the exact semantics, or suggest an improvement. Can anyone with a datasheet please suggest a proper patch to this line of code? TIA, Z. ====== Zoilo Gomez wrote: > In the mean time I have found that kernels 2.6.15 and 2.6.16 do not > suffer from this problem, whereas 2.6.22 till 2.6.25 do. > > Testing for kernels 2.6.17 till 2.6.21 is somewhat complicated in my > setup, because there are other problems (NFS-related) which I need to > sort out. > > So it looks like there is a bug somehow. > > Providing the dxs_support parameter does not make any difference, no > matter what value I set it to. > > Z. > > > Zoilo Gomez wrote: >> I have several J7F2 boards from Jetway, containing a 8237 via sound >> device on the south bridge. >> >> Using the alsa-driver, when I increase the volume then at some point >> all over sudden the sound stops. On some boards this happens at 75%, >> on others already at 60%, or 90%. Bringing the volume down again does >> not bring the audio back ... >> >> I am using the alsa-drivers with MPlayer. >> >> Although to me this smells like a hardware problem, I understand from >> googling around that this can be fixed with software, but I cannot >> find the correct solution anywhere. I have tested with gentoo kernels >> 2.6.22 and 2.6.24. >> >> AFAIK there are only 2 ways to get the sound back once it has stopped: >> >> 1) reset the mobo >> 2) rmmod snd-via82xx, followed by modprobe snd-via82xx >> >> The strange thing is that in option 2), the problem seems to be gone >> once the driver has been reloaded; from that moment on it is working >> fine ....! >> >> There is a driver from Via Arena (viaudiocombo) that seems to work >> fine, but it is OSS i.o. ALSA, and also a development by Via Arena >> i.o. the Linux community. Besides, I need synchronization features >> from the audio driver, and I do not think that OSS support this (not >> 100% sure). >> >> >> Can anyone help me and shed light on this? >> >> >> TIA! >> >> Zoilo. >> >> ------------------------------------------------------------------------- >> >> This SF.net email is sponsored by the 2008 JavaOne(SM) Conference >> Don't miss this year's exciting event. There's still time to save >> $100. Use priority code J8TL2D2. >> http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone >> >> _______________________________________________ >> Alsa-user mailing list >> Alsa-user@xxxxxxxxxxxxxxxxxxxxx >> https://lists.sourceforge.net/lists/listinfo/alsa-user >> >> >> > > > ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone _______________________________________________ Alsa-user mailing list Alsa-user@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-user
