On Sun, Dec 21, 2008 at 9:22 AM, naveenkrishna. ch < naveenkrishna.ch@gmail.com> wrote:
Hi ALSA SOC,
I am using a OMAP3 + TWL4030 combination with ASoC
in the sound/soc/omap/omap-pcm.c DMA channels are being freed after unlinking in the omap_pcm_hw_free function
Which is causing a crash during applications So, stopping the DMA channels before unlinking resolves the issue.
here is the patch that solves the issue
diff --git a/sound/soc/omap/omap-pcm.c b/sound/soc/omap/omap-pcm.c index e9084fd..679e384 100644 --- a/sound/soc/omap/omap-pcm.c +++ b/sound/soc/omap/omap-pcm.c @@ -116,6 +116,7 @@ static int omap_pcm_hw_free(struct snd_pcm_substream *substream) if (prtd->dma_data == NULL) return 0;
omap_stop_dma(prtd->dma_ch); if (!cpu_is_omap1510()) omap_dma_unlink_lch(prtd->dma_ch, prtd->dma_ch); omap_free_dma(prtd->dma_ch);Is this ok or is there any better way out
This looks a bit familiar, I hope so. Is this from linux-omap, mainline or in-house kernel?
There were similar issues fixed by following two patches in linux-omap. Second one is not yet in mainline, have to confirm with Tony has he queued it now.
commit 66c23551b1b774e2be3c7bdf91c0ebf2c7a3519e Author: Jarkko Nikula jarkko.nikula@nokia.com Date: Tue May 13 13:26:03 2008 +0300
ARM: OMAP: DMA: Don't mark channel active in omap_enable_channel_irq
Channel should be marked active only when DMA is really started. Otherwise just omap_request_dma, omap_dma_link_lch and omap_dma_unlink_lch will cause incorrect dump_stack().
commit 55502f74b56f609a84d8919b9b29390b2e0147ff Author: Jarkko Nikula jarkko.nikula@nokia.com Date: Mon Aug 18 12:28:22 2008 +0300
ARM: OMAP: DMA: Fix uninitialized channel flags
This has similar symptoms than 66c23551b1b774e2be3c7bdf91c0ebf2c7a3519e where just omap_request_dma, omap_dma_link_lch and omap_dma_unlink_lch can cause incorrect dump_stack(). Here it can happen if channel has been used before and the channel flags variable holds old status.
Signed-off-by: Jarkko Nikula jarkko.nikula@nokia.com Signed-off-by: Tony Lindgren tony@atomide.com
Then it's worth to verify also this very recent fix. This is already in mainline and will flow into linux-omap when Tony does the pull.
commit 19b3f31609dc8be3a56c78dcb7da723f10f7009c Author: Stanley Miao stanley.miao@windriver.com Date: Fri Dec 19 22:08:22 2008 +0800
ALSA: Fix a Oops bug in omap soc driver.
There will be a Oops or frequent underrun messages when playing music with omap soc driver, this is because a data region is incorretly sized, other da region will be overwriten when writing to this data region.
Jarkko