At Mon, 23 Feb 2009 22:21:24 +0530, Harsha, Priya wrote: > > Thank you. Can I use .ack callback to know that the mmaped buffer > has been filled by the user? Not really. It's just for explicit read/write modes. > How would I know how much the user has > written into the buffer that time? You can check appl_ptr at any time. This corresponds to the position the app has filled. Takashi > Would I need to have the pointers > calculated and tracked myself or is there a field in the structures > that I can read and find out? > > -----Original Message----- > From: Takashi Iwai [mailto:tiwai@xxxxxxx] > Sent: Monday, February 23, 2009 8:57 PM > To: Harsha, Priya > Cc: alsa-devel@xxxxxxxxxxxxxxxx > Subject: Re: clarification on mmap > > At Mon, 23 Feb 2009 18:59:11 +0530, > Harsha, Priya wrote: > > > > Hi, > > > > I have a question on mmap. If I give my .info to be _MMAP and > > _MMAP_VALID. Will ALSA framework internally take care of mmap-ing > > the kernel buffer that has been pre-allocated in the .probe call? Do > > I need to do anything special to mmap a kernel buffer into user > > space? Just accessing the runtime->dma_area would allow me to access > > user data right? > > Yes. The buffers allocated via preallocator are supposed to be > mmappable, so you can simply pass _MMAP* flag there. > > > Takashi > _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
