On Thu, Aug 12, 2010 at 8:56 PM, Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> wrote: > On Thu, Aug 12, 2010 at 06:15:47PM +0800, Randolph Chung wrote: >> I have a target that uses iMX27(L) + tlv320aic3x. The kernel tree is >> HEAD of linux-arm from about a week ago. >> >> Simple playback and recording (using aplay and arecord) work fine. >> However, I've run into a strange problem when both playback and >> capture streams are opened at the same time. >> >> Consider the attached test program. The capture device is setup with a >> period time of 10ms, and the program reads samples in a loop. The >> expected result is that I get a sample every 10ms. This works fine if >> the playback device is *not* opened (more specifically, if the >> hw_params are not set). However if the playback device is opened (#if >> 1 code) then I get samples every 20ms, which seems very wrong. >> >> I have tried using both DMA and FIQ ssi-pcm interfaces and both give >> the same strange result. With the FIQ driver, if I instrument the >> timer callback, the timer triggers every 10ms but there is only enough >> data every 20ms. >> >> The codec is being driven with a 13MHz MCLK (output from MX27) and the >> BCLK and WCLK come from the codec. They seem to have the correct >> rates. >> >> Any ideas? Can anybody else with MX27 hardware verify if my test >> program also fails on their target? > > You should check the return values of the snd_pcm_hw_params_* functions. > At least snd_pcm_hw_params_set_channels fails because we currently only > support two channels. I'm not sure whether we can support one channel > mode without changes to the driver. I will double check tomorrow, but I have another version of the code that checks all the return values and I am quite sure the set_channels didn't fail.... In any case why would it work if there is only a capture device open? Also I would imagine even if there are 2 channels the code should still work.... I would appreciate some test results on another mx27 board to verify if it is a problem specific to my setup or generic to other mx27 targets. thanks, randolph _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
