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authorAlan Stern <stern@rowland.harvard.edu>2011-10-25 10:50:58 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2011-11-14 17:05:03 -0800
commit2f640bf4c94324aeaa1b6385c10aab8c5ad1e1cf (patch)
tree498f41d40a6d6d34f93ecf7420fc7145fcd70d12 /drivers/usb
parent0d145d7d4a241c321c832a810bb6edad18e2217b (diff)
usb-storage: Accept 8020i-protocol commands longer than 12 bytes
The 8020i protocol (also 8070i and QIC-157) uses 12-byte commands; shorter commands must be padded. Simon Detheridge reports that his 3-TB USB disk drive claims to use the 8020i protocol (which is normally meant for ATAPI devices like CD drives), and because of its large size, the disk drive requires the use of 16-byte commands. However the usb_stor_pad12_command() routine in usb-storage always sets the command length to 12, making the drive impossible to use. Since the SFF-8020i specification allows for 16-byte commands in future extensions, we may as well accept them. This patch (as1490) changes usb_stor_pad12_command() to leave commands larger than 12 bytes alone rather than truncating them. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Tested-by: Simon Detheridge <simon@widgit.com> CC: Matthew Dharm <mdharm-usb@one-eyed-alien.net> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb')
-rw-r--r--drivers/usb/storage/protocol.c7
1 files changed, 3 insertions, 4 deletions
diff --git a/drivers/usb/storage/protocol.c b/drivers/usb/storage/protocol.c
index 93c1a4d86f5..82dd834709c 100644
--- a/drivers/usb/storage/protocol.c
+++ b/drivers/usb/storage/protocol.c
@@ -59,7 +59,9 @@
void usb_stor_pad12_command(struct scsi_cmnd *srb, struct us_data *us)
{
- /* Pad the SCSI command with zeros out to 12 bytes
+ /*
+ * Pad the SCSI command with zeros out to 12 bytes. If the
+ * command already is 12 bytes or longer, leave it alone.
*
* NOTE: This only works because a scsi_cmnd struct field contains
* a unsigned char cmnd[16], so we know we have storage available
@@ -67,9 +69,6 @@ void usb_stor_pad12_command(struct scsi_cmnd *srb, struct us_data *us)
for (; srb->cmd_len<12; srb->cmd_len++)
srb->cmnd[srb->cmd_len] = 0;
- /* set command length to 12 bytes */
- srb->cmd_len = 12;
-
/* send the command to the transport layer */
usb_stor_invoke_transport(srb, us);
}