Re: Bugs in scsi_vpd_inquiry()

Douglas Gilbert
2009-08-10T21:53:54Z

Martin K. Petersen wrote:
>>>>>> "Alan" == Alan Stern <stern@rowland.harvard.edu> 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