[alsa-devel] playback write error(DMA or IRQ trouble?)

innoway at mymelody.com innoway at mymelody.com
Fri May 20 07:10:16 CEST 2011

 I develop an embedded system on the Linux board with Freescale i.MX27
(ARM processor).   I succeed on sound, which is transferred using
Synchronous Serial Interface (SSI). It,s fine and then I try to do test
of inserting or pulling out a USB memory stick in the USB host connector
while sounding.   I get the following error message from
snd_pcm_lib_write1() of <linux src>/sound /core/pcm_lib.c after waiting
for a while (about 10sec).       playback  write error (DMA or IRQ
trouble?)   and then from snd_pcm_drain() of <linux
src>/sound/core/pcm_native.c      playback drain error (DMA or IRQ
trouble?)   (No sound during this period)

and then it is sounding again.

I want to prevent the sound from stopping even if something happens
suddenly such as the USB memory stick is plugged in or out.

I try to fix the above programs, but I don't succeed.

Can someone give me the clue?   [13:21:38]:/proc# cat interrupts
 12:       3456         -  mxc_i2c
 16:        141          -  CSPI_IRQ
 18:        952          -  mxcintuart
 26:    1051255     -  MXC Timer Tick
 28:      29446        -  PCMCIA IRQ, ide0
 50:         33           -  fec
 54:        793          -  ehci_hcd:usb1
 56:          1            -  arc_udc
 61:          0            -  LCDC
117:          0           -  m66291_udc
147:          0           -  PMIC_IRQ
157:     337179     -  SMSC_LAN911x_ISR
176:          0           -  fec(MII)

[13:35:03]:/proc# cat dma
dma channel  0: unused
dma channel  1: unused
dma channel  2: unused
dma channel  3: unused
dma channel  4: unused
dma channel  5: unused
dma channel  6: unused
dma channel  7: unused
dma channel  8: unused
dma channel  9: unused
dma channel 10: unused
dma channel 11: unused
dma channel 12: unused
dma channel 13: unused
dma channel 14: unused
dma channel 15: unused   Thank you

Masanori Inoue

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