Takashi Iwai wrote: > At Mon, 28 Apr 2008 23:39:04 +0200, > Zoilo Gomez wrote: > >> (Sorry for cross-posting from alsa-user; however, on 2nd thought I think >> this really belongs in alsa-devel): >> >> === >> >> 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. >> > > Appreciated that you hunted it out. > Added Cc to the patch author. > Thank you for your response, Takashi! >> 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? >> > > The register 0x5c is the VIA specific one. I have a VT1617 (without > A) datasheet, and it suggests that the bit corresponds to the > "headphone amplifier temperature sensing control". And setting this > bit means to _disable_ the temperature sensing control. This sounds > rather the correct to set. > > However, I don't know whether any difference exists betweeen VIA1617 > and 1617A although the codec id of both are identical. > > Andrey, any comments about your patch? > > > In anyway, it'd be helpful if we can know which ac97 registers work > and wich not. Please take /proc/asound/card0/codec97#*/ac97#*-regs > file in both working and non-working cases to compare. Especially, > the registers 0x5a and 0x5c look interesting. > Code containing "snd_ac97_write_cache(a97, 0x5c, 0x20)": 0x5a = 8300 0x5c = 0000 Code with "snd_ac97_write_cache(a97, 0x5c, 0x20)" commented out: 0x5a = 8301 0x5c = 0020 Quite a surprise to me, I would have expected exactly the opposite .....!? Can you explain this? /proc/asound/card0/codec97#0/ac97#0-0+regs does dump current registers, correct? Or is it a toggling bit? Thank you, Zoilo. > > Thanks, > > Takashi > > > > >> 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 >>>> >>>> >>>> >>>> >>> >>> >> >> _______________________________________________ >> Alsa-devel mailing list >> Alsa-devel@xxxxxxxxxxxxxxxx >> http://mailman.alsa-project.org/mailman/listinfo/alsa-devel >> >> > > > _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
