On Wed, Mar 4, 2009 at 2:34 AM, Daniel Mack <daniel@xxxxxxxx> wrote: > Hi Phillip, > > glad to see someone is wasting time with that issue, too :) > > On Tue, Mar 03, 2009 at 04:10:51PM +0100, Philipp Zabel wrote: >> For consistency with 24-bit and 32-bit modes, don't send 16-bit stereo >> in one 32-bit transfer. Use 2 slots instead on Zylonite. It should result >> in exactly the same behaviour. >> Now it is possible to use 16-bit single slot transfers in pxa-ssp, which >> are needed for Magician to get two frame clock pulses per sample >> (one for each channel). > > We've been fiddling around with these modes and registers for > another two days in a row now and figured out that literally all the > documentation about these registers is entirly bogus. In particular, > the network mode with the associated timeslots simply does not work at > all, according to our measurements. > > Hence the question: how does your I2S signal look like at the moment? > How many clocks do you measure in one frame cylce, how many of them are > actually filled with data? And which format does the userspace use to > send samples in? Unfortunately, I can't measure anything. I don't own an oscilloscope and I don't even know if there are useful test points on the phone's mainboard. Also, I've come to the conclusion that on Magician there has to be some kind of flip-flop between the PXA272's SSPFRMCLK and the codec's LRCLK input. I'm not using I2S mode at all, but TISSP (or PSP with DAIFMT_DSP_A) and two full frames per sample. I can more or less handle S16_LE and S32_LE from userspace now. Using S24_LE doesn't work because the codec supports LSB aligned signals only up to 20-bit. S24_3LE I didn't try yet, but the PXA DMA can't advance the source pointer by 3 bytes per transfer, so that would be ugly anyway (and only possible if network mode works). > We finally got a mode now that outputs 2x16 bit on a 2x32 bits I2S > frame, padded with zeros. But that is in non-network modes, more > about that tomorrow ... Strange, interesting ... regards Philipp _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
