On 05/16/2013 10:56 AM, Torstein Hegge wrote: > On Thu, May 16, 2013 at 09:48:42 +0200, B. Zhang wrote: >> On 05/15/2013 10:25 PM, B. Zhang wrote: >>> Hi, >>> >>> Using mpd and kernel 3.9.2, when I switch tracks and the next >>> track is a different sample rate there is a fairly loud popping. >>> There is no noise during playback. Sometimes this happens even the >>> next track has the same sample rate. >>> I use a usb interface is M2Tech hiface2 (XMOS UAC2, >>> http://www.m2tech.biz/hiface2.html ). >>> >>> But it works with kernel 3.1.10. >>> >>> It seems this is a synchronization lost problem with soft mute DAC. >>> >>> I wonder if this problem is related to usb feedback (the hiface2 >>> is asynchronous). >>> With kernel 3.1.10, Feedback Format = 16.16 >>> With kernel 3.9.2, Feedback Format = 8.16 Packet Size = 0 >> Maybe it's a URBs problem ? >> URBs = 8 [ 8 8 8 8 8 8 8 8 ] when using 3.1.10, but not this line >> with 3.9.2. > No, both of those are caused by changes in the proc output. The URB line > was removed in kernel 3.5. > > There seems to be something wrong with the feedback format output, > as freqshift is only set for the data_endpoint, but syncmaxsize is only > set for the sync_endpoint. I'll try to come up with a fix for that. kernel 3.4.45 works fine. It also has the correct feedback format "Feedback Format = 16.16" > > As to your actual problem with the pops, I don't have any ideas. Do you > get the same behavior when stopping and starting playback? Yes. Stop or Pause. With kernel 3.7, my usb sound interface didn't work: ======== Feb 14 09:05:40 alarm kernel: [ 1184.097631] ERROR: 1024 KiB atomic DMA coherent pool is too small! Feb 14 09:05:40 alarm kernel: [ 1184.097631] Please increase it with coherent_pool= kernel parameter! Feb 14 09:05:40 alarm kernel: [ 1184.110240] cannot submit urb (err = -12) Feb 14 09:05:41 alarm kernel: [ 1184.257263] cannot submit urb (err = -12) Feb 14 09:05:41 alarm kernel: [ 1184.261340] cannot submit urb (err = -12) ... ============== This was fixed since kernel 3.8.6: pb: http://www.mail-archive.com/linux-kernel@xxxxxxxxxxxxxxx/msg373053.html patch: https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/drivers/usb/host/ehci-sched.c?id=85ecd0322b9a1a9f451d9150e9460ab42fd17219 Thanks, Bin > > > Torstein ------------------------------------------------------------------------------ AlienVault Unified Security Management (USM) platform delivers complete security visibility with the essential security capabilities. Easily and efficiently configure, manage, and operate all of your security controls from a single console and one unified framework. Download a free trial. http://p.sf.net/sfu/alienvault_d2d _______________________________________________ Alsa-user mailing list Alsa-user@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-user
