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Commit 8e04d805 authored by Hans de Goede's avatar Hans de Goede Committed by Greg Kroah-Hartman
Browse files

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: default avatarHans 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 319feaab

drivers/scsi/sr.c

+7 −1
Original line number Diff line number Diff line
@@ -862,10 +862,16 @@ static void get_capabilities(struct scsi_cd *cd) 
static int sr_packet(struct cdrom_device_info *cdi,

		struct packet_command *cgc)

{

	struct scsi_cd *cd = cdi->handle;

	struct scsi_device *sdev = cd->device;



	if (cgc->cmd[0] == GPCMD_READ_DISC_INFO && sdev->no_read_disc_info)

		return -EDRIVE_CANT_DO_THIS;



	if (cgc->timeout <= 0)

		cgc->timeout = IOCTL_TIMEOUT;



	sr_do_ioctl(cdi->handle, cgc);

	sr_do_ioctl(cd, cgc);



	return cgc->stat;

}

include/scsi/scsi_device.h

+1 −0
Original line number Diff line number Diff line
@@ -148,6 +148,7 @@ struct scsi_device { 
	unsigned retry_hwerror:1;	/* Retry HARDWARE_ERROR */

	unsigned last_sector_bug:1;	/* do not use multisector accesses on

					   SD_LAST_BUGGY_SECTORS */

	unsigned no_read_disc_info:1;	/* Avoid READ_DISC_INFO cmds */

	unsigned is_visible:1;	/* is the device visible in sysfs */



	DECLARE_BITMAP(supported_events, SDEV_EVT_MAXBITS); /* supported events */