At Wed, 19 Aug 2009 18:59:31 +0800, Shine Liu wrote: > > On Wed, 2009-08-19 at 12:34 +0200, Takashi Iwai wrote: > > At Wed, 19 Aug 2009 18:22:19 +0800, > > Shine Liu wrote: > > > > > > There's no restriction on that the runtime->period_size should be the > > > multiplicator of the runtime->buffer_size in current kernel code. > > > > > > So "hw_ptr_interrupt = runtime->hw_ptr_interrupt + > > > runtime->period_size;" is not always the trueth. > > > > The hw_ptr_interrupt is the expected position where the current irq is > > issued. So, the current code should be correct -- it's simply > > increased in the size of period_size. > > Yes, the period_size and buffer_size I used was 0x800 and 0x3e80. > > The log from the kernel is : > > period_update: pcmC0D0p:0: pos=0x809/0x800/0x3e80, hwptr=0x1c, hw_base=0x0, hw_intr=0x0 > period_update: pcmC0D0p:0: pos=0x1008/0x800/0x3e80, hwptr=0x809, hw_base=0x0, hw_intr=0x800 > period_update: pcmC0D0p:0: pos=0x1808/0x800/0x3e80, hwptr=0x10e3, hw_base=0x0, hw_intr=0x1000 > period_update: pcmC0D0p:0: pos=0x2006/0x800/0x3e80, hwptr=0x1808, hw_base=0x0, hw_intr=0x1800 > period_update: pcmC0D0p:0: pos=0x2808/0x800/0x3e80, hwptr=0x203f, hw_base=0x0, hw_intr=0x2000 > period_update: pcmC0D0p:0: pos=0x3008/0x800/0x3e80, hwptr=0x2808, hw_base=0x0, hw_intr=0x2800 > period_update: pcmC0D0p:0: pos=0x3808/0x800/0x3e80, hwptr=0x30e9, hw_base=0x0, hw_intr=0x3000 > period_update: pcmC0D0p:0: pos=0x8/0x800/0x3e80, hwptr=0x3808, hw_base=0x0, hw_intr=0x3800 > PCM: Unexpected hw_pointer value (stream=0, pos=8, intr_ptr=16384) > > It's true that irq was issued when hw_ptr_interrupt is > 0x800,0x1000,0x1800,...,0x3800,0x3e80. > > But the irq last issued should be at 0x3e80, but not 0x3800 + 0x800 = > 0x4000. The DMA engine loaded 0x680 frame not 0x800 frame at the last > time. Then it's a driver bug. If unaligned period size is allowed, it means that the irq is really generated in that period, not at the buffer boundary. Otherwise, it must have a proper hw-constraint to align the period size to the buffer size. What hardware is it? thanks, Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
