On Wed, May 12, 2010 at 05:19:36PM +0530, Ajay Kumar Gupta wrote: > MUSB RTL version 1.4 has a hardware issue when TX and RX DMA channels are > simultaneously enabled which results in DMA lockup. I've seen it on rtl1.8 also if I remember correctly. > Use system DMA for all RX channels as a workaround of this issue as this > will have minimal throughput overhead based on the fact that Rx transfers > are done in DMA mode-0 on OMAP34x/35x platforms. > > Another approach to use PIO mode in opposite direction would increase the > cpu loading and thus using system DMA is preferred workaround. > > Signed-off-by: Anand Gadiyar <gadiyar@xxxxxx> > Signed-off-by: Ajay Kumar Gupta <ajay.gupta@xxxxxx> I think falling back to pio is better than this patch. It will most likely be only one transfer. Another approach is to allocate dma channels on a transfer basis. This is way too big of a problem. -- balbi -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
