On Mon, Sep 28, 2015 at 6:23 AM, Viresh Kumar <viresh.kumar@xxxxxxxxxx> wrote: > On 26 September 2015 at 05:38, yitian <yitian.bu@xxxxxxxxxxxxxx> wrote: >> 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@xxxxxxxxxxxxxx> >> --- >> drivers/dma/dw/core.c | 6 +----- >> 1 file changed, 1 insertion(+), 5 deletions(-) > > I am not sure if this is a sane way of doing that, and we were scanning > the descriptors for some valid reason.. Actually one of the patches in a pile sitting in my private repo is also including similar change. In my case the reason is to support cyclic transfers natively. > Though, I am on vacation for few days now and will be able to look > at the details later. Have a good rest then! -- With Best Regards, Andy Shevchenko -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
