Hi James, could you create a patch to the source (alsa-kernel/Documentation/DocBook/writing-an-alsa-driver.tmpl)?
it's just a DocBook format. the tmpl extension is used to allow the inclusion from the kernel source, although this document doesn't do it. thank,s Takashi At Sat, 08 May 2004 19:33:51 +0000, James Courtier-Dutton wrote: > > I have been helping some people with writing alsa drivers. > One thing that they did not totally understand from the alsa > documentation was the concept of frames. > To help with this, could we add a html link between in the following > document: - > http://www.alsa-project.org/~iwai/writing-an-alsa-driver/x490.htm > > In section: - > /* pointer callback */ > > pointing to: - > http://www.alsa-project.org/~iwai/writing-an-alsa-driver/x537.htm > > In Section: - > PCM Configurations > > Where it explains about what a "frame" is. > I think it would be helpful to also explain that the document: - > http://www.alsa-project.org/~iwai/writing-an-alsa-driver/x490.htm > > has a line: - > current_ptr = mychip_get_hw_pointer(chip); > > I think that comments should be added close to that line to say: - > " > The pointer value obtained from the hardware is likely to be a byte > offset within the buffer. In order to convert this value to a type > "snd_pcm_uframes_t" , that is required as the return value, use the > following code: - > return bytes_to_frames(substream->runtime, pointer); > > An explanation of what a "frame" is can be found at http://xyz > " > > Or just change the document example code: - > /* pointer callback */ > static snd_pcm_uframes_t > snd_mychip_pcm_pointer(snd_pcm_substream_t *substream) > { > mychip_t *chip = snd_pcm_substream_chip(substream); > - unsigned int current_ptr; > + unsigned int current_byte_ptr; > > // get the current hardware pointer > - current_ptr = mychip_get_hw_pointer(chip); > - return current_ptr; > + current_byte_ptr = mychip_get_hw_pointer(chip); > + return bytes_to_frames(substream->runtime, current_byte_ptr); > > } > > > Cheers > James > > > ------------------------------------------------------- > This SF.Net email is sponsored by Sleepycat Software > Learn developer strategies Cisco, Motorola, Ericsson & Lucent use to deliver > higher performing products faster, at low TCO. > http://www.sleepycat.com/telcomwpreg.php?From=osdnemail3 > _______________________________________________ > Alsa-devel mailing list > [EMAIL PROTECTED] > https://lists.sourceforge.net/lists/listinfo/alsa-devel > ------------------------------------------------------- This SF.Net email is sponsored by Sleepycat Software Learn developer strategies Cisco, Motorola, Ericsson & Lucent use to deliver higher performing products faster, at low TCO. http://www.sleepycat.com/telcomwpreg.php?From=osdnemail3 _______________________________________________ Alsa-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/alsa-devel
