> From: Sarah Sharp ... > (Also, usb-storage aligns the block sizes to 512K, which explains why > we've never had an issue with TD fragments with that driver.) What is a 'block' in that context? 512K sounds more like the value that very long transfers get chopped up into. With 4k pages that might be 128 fragments. I'd have thought that the SG list would normally contain references to a number of memory pages - so each would be 4k (on x86) aligned. My suspicion is that the xhci controller will generate correct USB3 data provided the link TRB is on a 1k boundary - so such data won't be a problem. If a user program does a direct transfer from the block device (and that is done by locking down the user pages) then the buffer could have an arbitrary alignment. David -- 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
