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    scsi/sr: add no_read_disc_info scsi_device flag · 8e04d805
    Hans de Goede 提交于
    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: NHans 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: NAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
    8e04d805
scsi_device.h 16.9 KB