On Mon, Oct 24, 2011 at 11:45 AM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > On Mon, 24 Oct 2011, Matthew Dharm wrote: > >> Good point. >> >> That said, I'm also not certain that you want to change UFI. Unlike >> the other transports, UFI was written (as far as I know) for USB >> devices. And I believe it says commands shall be 12 bytes only. So, >> allowing larger commands might be counter-productive. > > All right, I'll remove that part of the patch. > > Section 4.5.1 of the SFF-8020i spec allows for both 12-byte and 16-byte > commands. The size is supposed to be determined by the first byte of > data returned by the ATAPI Identify Device command, but that command > isn't available over a non-ATA transport. > > I guess it's reasonable to assume that all commands larger than 12 > bytes should be padded to 16 bytes. Does SCSI include any 13-, 14-, or > 15-byte commands? I don't think so. So it should be okay to just > remove the line setting srb->cmd_len to 12. To my knowledge, 13, 14, or 15 isn't in any of the standard commands. But, vendor-specific commands can be any length. I think padding up to 12 (when less), and leaving anything bigger, is probably the way to go. > Does that sound reasonable? I think so. Matt -- Matthew Dharm Maintainer, USB Mass Storage driver for Linux -- 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
