Messages in this thread Patch in this message | | | From | "yitian" <> | Subject | [PATCH 1/1] dmaengine: dw: resolve recursion lock when audio playback | Date | Sat, 26 Sep 2015 20:38:47 +0800 |
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when audio playback is running, user space will call snd_pcm_lib_write1() function, it will first get pcm stream lock, after that it may call function snd_pcm_update_hw_ptr(), the call stack will be as below: snd_pcm_lib_write1 <-- got pcm stream lock --> snd_pcm_update_hw_ptr --> dwc_tx_status --> dwc_scan_descriptors --> callback --> dmaengine_pcm_dma_complete --> snd_pcm_period_elapsed <-- get stream lock again recursion lock occurs in snd_pcm_period_elapsed function. remove dwc_scan_descriptors from dwc_tx_status can fix this issue.
Signed-off-by: Yitian Bu <yitian.bu@tangramtek.com> --- drivers/dma/dw/core.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-)
diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c index cf1c87f..5341b44 100644 --- a/drivers/dma/dw/core.c +++ b/drivers/dma/dw/core.c @@ -1078,11 +1078,7 @@ dwc_tx_status(struct dma_chan *chan, ret = dma_cookie_status(chan, cookie, txstate); if (ret == DMA_COMPLETE) return ret; - - dwc_scan_descriptors(to_dw_dma(chan->device), dwc); - - ret = dma_cookie_status(chan, cookie, txstate); - if (ret != DMA_COMPLETE) + else dma_set_residue(txstate, dwc_get_residue(dwc)); if (dwc->paused && ret == DMA_IN_PROGRESS) -- 1.7.12.4
Yitian Best Regards
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