[lkml]   [2005]   [Nov]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread

    finally the em28xx driver made it into the kerneltree, but one problem
    still remains
    the snd_usb_audio driver.

    the em28xx driver various framegrabber devices (pinnacle, hauppauge,

    The problem with the snd_usb_audio driver is that it only supports up
    to 10 isochronous packets. If people watch TV using such a
    framegrabber device and set audio to >8000hz the video isoc transfer
    will break and the video will stop.

    regarding usbaudio.c (in 2.6.14):
    #define MAX_PACKS 10
    #define MAX_PACKS_HS (MAX_PACKS * 8) /* in high speed mode */

    MAX_PACKS is the upper limit that is adjustable, the second one isn't
    used at all

    an easy hack would be to allow up to 100 packets but I also have a usb
    1.1 soundblaster that might have problems with too many packets.

    The correct value for em28xx devices is around 80 packets.

    does anyone know more about the packet limitations on USB 1.1 and 2.0 devices?
    MAX_PACKS_HS isn't used anywhere, but defined as MAX_PACKS * 8. I
    don't know if it's just safe to say MAX_PACKS * 8 would fit for high
    speed devices.

    Unless this bug isn't fixed the em28xx driver is quite useless in the
    kerneltree since it will not work with digital usb audio

    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at

     \ /
      Last update: 2005-11-16 00:20    [W:0.020 / U:0.556 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site