On Wed, Feb 17, 2010 at 12:02:21PM -0500, Alan Stern wrote: > Why do you skip mapping the setup packet but not the data packet? This is something of a FAQ in this thread. Here are the responses to similar questions yesterday: "Gadiyar, Anand" <gadiyar@xxxxxx> said: > Not really. For instance, in the case of the DMA engine in the MUSB > controller in OMAP3, we can only use DMA with endpoints other than > EP0, and EP0 is what is used for control transfers. > > It's not PIO for all the endpoints or DMA for all of them. "Shilimkar, Santosh" <santosh.shilimkar@xxxxxx> said: > On the OMAP4 (ARM cortex-a9) platform, the enumeration fails because control > transfer buffers are corrupted. On our platform, we use PIO mode for control > transfers and DMA for bulk transfers. > > The current stack performs dma cache maintenance even for the PIO transfers > which leads to the corruption issue. The control buffers are handled by CPU > and they already coherent from CPU point of view. -- 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
