Re: [usb-storage] Re: [PATCH] fix Sony USB mass storage - pass larger receive buffer

Matthew Dharm
2003-11-14T02:19:50Z

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On Thu, Nov 13, 2003 at 07:10:34PM -0700, Pat LaVarre wrote:
> Can we blacklist mode sense from bInterfaceSubClass = xFF?
>
> That way we don't break as many write-protectable devices as if we
> blacklisted mode sense always?
>
> I remember today already I once proposed blacklisting only
> bInterfaceSubClass = xFF, Matt said no once, I don't think I yet grok
> Matt's no.
>
> Can we blacklist only xFF if I wrote the patch myself?

Perhaps I didn't understand what you were asking....

To blacklist bInterfaceSubClass = 0xFF, you'll have to do that at the
usb-storage layer (not the SCSI layer). I generally object to that, but
not very strongly -- I want usb-storage to be as simple/dumb as possible,
to reduce to number of places where it doesn't do what the end-user
expects. (The principle of least suprise)

If the blacklist was implemented such that it only blacklisted
direct-access devices, and only MODE_SENSE and MODE_SENSE_10, and provided
fake sense data, then it would probably work. Messy, but it would work.

The point is to create as narrow an exception as possible.

Matt

--
Matthew Dharm Home: mdharm-usb@one-eyed-alien.net
Maintainer, Linux USB Mass Storage Driver

Umm, these aren't the droids you're looking for.
-- Bill Gates
User Friendly, 11/14/1998

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