On Wed, Sep 12, 2012 at 02:47:07PM +0300, Peter Ujfalusi wrote: > 2. Pause/Resume > OMAP DMA engine backend does not support pausing and resuming > an in-progress transfer. It is unclear from the specs what > effect clearing the enable bit has on the DMA position of a > destination synchronized transfer, and whether the transfer > can be restarted from the exact point that it was paused (or > whether the data in the FIFO read from memory is simply > discarded.)
It's worth noting that this comment (which was in my original patch) is there to spark _comment_ and _discussion_ and should not make its way into the final version of these patches. Given that suspend/resume is important on OMAP platforms, it's something that needs to be resolved - in a way that complies with what ALSA expects. I do not believe that the way the existing drivers do this is compliant as the manuals imply that stopping memory->peripheral transfers results in data being discarded from the DMA's FIFOs. As I understand it, ALSA requires no data to be discarded. As we have no way to know how much data may be discarded from the DMA FIFO... -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
