On 07/19/2013 09:59 AM, Rajaram R wrote: >> Okay. musb offloads the actual transfer to the DMA engine it is using. >> Once it does so, it relies on whatever comes back from dma engine >> regarding transfer complete, transferred size etc. > > AFAIK ux500 musb dma code handles data which is multiple of max packet > size in DMA. 1 byte should be in PIO mode. Which version of kernel you > are using ? I am looking at v3.11-rc1 right now and I don't have the HW. As I said: The URB scheduled for receive is 256 bytes in size, max packet size is 64. So DMA should be chosen, right? The UART on other side sends just one byte so the DMA receives just one byte regardless what has been requested. My question is how musb gets notified of this one byte. It might happen someplace but I don't see it. Sebastian -- 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
