On 03/18/2013 04:59 AM, Bo Shen wrote: > Hi Lars, > > On 3/17/2013 22:39, Lars-Peter Clausen wrote: >> Hi, >> >> The dmaengine based pcm driver for atmel calls snd_dmaengine_pcm_open from >> it's hw_params callback. There is nothing preventing an application calling >> hw_params more than once. snd_dmaengine_pcm_open allocates a new prtd struct >> each time it gets called. So in case hw_params is called multiple times we >> leak memory here. > > I use alsa utils and don't meet this issue. Please point out which software > you use meet this issue. I found the issue by looking at the code, but I think any application using the oss compatibility layer of ALSA will trigger this. > >> Is there any specific reason why snd_dmaengine_pcm_open() needs to be called >> from the hw_params callback and why it can't be called from the open >> callback? > > This is because dma data setting and usage. > > The filter function depends on the data returned by >> snd_soc_dai_get_dma_data(), but as far as I can see the DAI driver calls >> snd_soc_dai_set_dma_data() from its startup() callback, so the data is >> available in the PCM drivers open callback. > > Have you test this yet? I don't have the hardware. I just looked at the code again, and it looks like I must have misread it the first time. snd_soc_dai_set_dma_data() is called from the DAI drivers hwparams callback. But the data that gets passed to snd_soc_dai_set_dma_data() doesn't really depend on anything that's only available in the hwparams callback. So the snd_soc_dai_set_dma_data() could easily be move to the DAI driver startup() callback. - Lars _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
