Thanks for your suggestion. I do agree with you. But when I change my period_size to 4KB and set number of periods to 16, my hw_ptr or appl_ptr never move from their initial value of 0. So you think this a driver problem? But the hw_ptr is not something the driver controls? Would appreciate if you could explain more on this. Thanks. Prabhu. On 5/3/07, Jaroslav Kysela <perex@xxxxxxx> wrote: > On Thu, 3 May 2007, Prabhu Sivaraja wrote: > > > Hi, > > > > I've been stuck on this dmix problem for the past week and have tried > > everything under the sun. Please any help or comment is much > appreciated. > > Thanks a lot. > > For nice dmix support, it's better to have more periods than 2 and small > ones. Your allowed configuration 2 x 32KB is not very good. > > But judging from the current dmix code, this code may cause to skip large > count of samples or your driver behaves badly: > > /* If we have too litte periods, better to align the start position > * to the period boundary so that the interrupt can be handled properly > * at the right time. > */ > dmix->slave_appl_ptr = ((dmix->slave_appl_ptr + dmix->slave_period_size - > 1) > / dmix->slave_period_size) * > dmix->slave_period_size; > > > It's from changeset: > > hangeset: 2109:349c0b0018b9 > user: tiwai > date: Fri Mar 24 14:53:41 2006 +0000 > files: src/pcm/pcm_direct.c src/pcm/pcm_dmix.c > description: > Fix noisy output of dmix with two periods > > Fixed the noisy output of dmix with two (or less) periods. > The dmix tends to give noise or XRUN when running with two periods > because of its implementation nature. To avoid this, the start > position is aligned to the period size, so that the updates are synced > with interrupts of slave PCM. > > > So in order to debug this I tried to decrease my period_size = 4KB but > when > > I do this my hw_ptr never moves. > > Driver problem? > > Jaroslav > > ----- > Jaroslav Kysela <perex@xxxxxxx> > Linux Kernel Sound Maintainer > ALSA Project, SUSE Labs > _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
