At Thu, 17 May 2012 17:15:24 +0800, cee1 wrote: > > Hi, > > Thanks for reply. > 2012/5/15 Takashi Iwai <tiwai at suse.de> > > > > At Tue, 15 May 2012 16:30:14 +0800, > > cee1 wrote: > > > > > > Witch a patch[1] of PA which dumps playback PCM data, I found the > > > dumped data(with ./wavformat.py[2] <dumpped_data> to convert to wav > > > file) is not corrupted. > > > Since PA uses mmap to transfer PCM data, the driver's DMA buffer > > > should also be "good". > > > > > > It seems related to HDA controller of SB710, I tried HDMI output, and > > > can reproduce the problem > > > too(http://dev.lemote.com/files/upload/software/PA-apc/HDMI-corrupted_sound.ogg). > > > > If you are using the recent kernel, try snoop=off option of > > snd-hda-intel driver. ?The recent AMD and VIA controllers are known to > > work with the non-snooping mode. > > I'm trying?snd-hda-intel.snoop=0 under ubuntu10.10(32bit) with kernel > from ubuntu 12.04(32bit), I still can reproduce it. > > BTW, what is difference between snoop and no snoop? > Enable no snoop mode will render no sound on our platform(which is > mips compatible). Ah, *this* is the biggest missing information. The non-snoop mode is implemented currently only for x86-64. The non-snoop mode requires the non-cached pages and its mmap. This implementation is pretty arch-dependency, and currently no properl way is provided for MIPS. On such platforms, mmap doesn't work reliably, unfortunately. Takashi
