Hi Bin, Thanks for reply. It really helped. I got it working and I would like to share my solution just in case some one faces similar issue. When I traced the function usb_hcd_map_urb_for_dma it checks first for CONFIG_HAS_DMA fla set and uses_dma so when this if condition passes it goes to dma_map_single which was causing problem. So I have used uses_dma=n as command-line argument which made first if loop fail and go to else if which allocates memory in ram using hcd_alloc_coherent So this is how I was able to disable dma. Thanks Every on who helped me to solve this issue. I am glad to see so active community where I got response to my question within couple of hours. I am grateful to you guyz. Regards Devidas Jadhav -- 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
