On Wed, 22 Apr 2009 20:05:40 +0200 "ext Menon, Nishanth" nm@ti.com wrote:
Test tone is being presented by the user application, providing a 1Khz tone sampled at 44.1Khz. The data are S16_LE, right channel only. Left channel is quiet. The data seems to slip back and forth from left to right channel. This is reproducable and verified with a scope trace.
Is this slipping happening in middle of playback or between the tracks?
I recollect this issue from years back of OSS driver -> i2s is configured as dual phase - mcbsp sends data on both edges, and if the data write happen on the wrong edge for the wrong phase, we might get mix up.. if I recollect right, configuration for mcbsp was done as a single phase with the right edge as a trigger for transfer, the transfer size was set as 32 bytes (both channels).. this essentially guarentees that mcbsp will never mix up channels.
Thanks Menon! This is sounds a information we should try out. OMAP2420 in N810 is especially suffering from channel swapping between the tracks and I haven't found time to look any deeper :-(
I know there is a fix for DaVinci (commit fb0ef645f2c546f8297b2fbf9b2b8fff4a7455e8) but I would like to find out are there any other or simpler way to fix it than mixing DMA and DAI setup.
Jarkko