scsi/sr: add no_read_disc_info scsi_device flag
authorHans de Goede <hdegoede@redhat.com>
Fri, 1 Oct 2010 21:20:08 +0000 (14:20 -0700)
committerGreg Kroah-Hartman <gregkh@suse.de>
Fri, 22 Oct 2010 17:22:04 +0000 (10:22 -0700)
commit8e04d8056c1ea0e0aab730994b74756f0526cda8
treeb81a3e2f5993c69559d120fa96840e1ef70b42d4
parent319feaabb6c7ccd90da6e3207563c265da7d21ae
scsi/sr: add no_read_disc_info scsi_device flag

Some USB devices emulate a usb-mass-storage attached (scsi) cdrom device,
usually this fake cdrom contains the windows software for the device.
While working on supporting Appotech ax3003 based photoframes, which do
this I discovered that they will go of into lala land when ever they see a
READ_DISC_INFO scsi command.

Thus this patch adds a scsi_device flag (which can then be set by the
usb-storage driver through an unsual-devs entry), to indicate this, and
makes the sr driver honor this flag.

I know this sucks, but as discussed on linux-scsi list there is no other
way to make this device work properly.

Looking at usb traces made under windows, windows never sends a
READ_DISC_INFO during normal interactions with a usb cdrom device.  So as
this cdrom emulation thingie becomes more common we might see more of this
problem.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/scsi/sr.c
include/scsi/scsi_device.h