On Tue, 15 Dec 2009, Gadiyar, Anand wrote: > For g_ether, the buffers are allocated using kmalloc(), but the > networking code seems to move the data in the buffer out by 2 > bytes, and passes this unaligned address down to the gadget driver. > > The MUSB controller in the beagleboard could handle these unaligned > DMA address, but looks like newer MUSB controllers don't seem to > like this. This is different from the point made in the earlier message (that buffers need to be aligned for clean/invalidate/flush buffer). Assuming you can't get the network layer to avoid moving the data out, you could modify either the controller driver or g_ether. It's probably best to make g_ether move the data back to the beginning of the buffer. The USB stack generally has strict requirements on data alignment (because of the need to use maxpacket-sized DMA transfers). Alan Stern -- 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
