Martin K. Petersen wrote:
"Alan" == Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> writes:
Alan,
data always to be accurate may not be a good idea. I'm considering
adding a "restrict_to_MS_usb" flag to the host template, to
indicate that commands shouldn't be sent unless some version of
Windows uses them when talking to USB devices -- do you think that
could work?
Not really my area of expertise.
Alan> Okay. Maybe Martin has some thoughts on it.
First of all we're not going to send EVPD=1 out to devices reporting
SCSI_SPC_2 or lower anymore, making some of this discussion moot in the
short term.
But as I have alluded to in the past we do have a conflict brewing
because the switch to drives with 4KB physical blocks will mean USB
bridges will have to get smarter. And that in turn will mean adhering
(*gasp*) to the standard instead of firmware writers flipping bits until
Windows stops crashing. Windows 7 does in fact query drives about
alignment, block sizes, etc. But I'm not sure how true that is for the
Windows USB storage stack.
It would be interesting to know if Windows 7 is pushing
UAS (USB attached SCSI) [latest draft at www.t10.org is
uas-r02.pdf].
"USB Attached SCSI is a new generation of USB Transport
Standards. This standard supports the following
features in support of USB-20 and future USB
specifications:
a) does not interfere with the USB Mass Storage Class
(MSC) bulk-only transport;
b) mechanism to send commands associated with any T10
standard to a USB device;
c) support for queuing in the protocol;
d) support for autosense;
e) compliance with SCSI Architecture Model - 4 (SAM-4)
or later; and
f) other capabilities."
It is at the letter ballot stage at t10.
Doug Gilbert
--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
