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authorAlan Stern2011-06-07 11:35:52 -0400
committerGreg Kroah-Hartman2011-06-07 09:05:42 -0700
commit21c13a4f7bc185552c4b402b792c3bbb9aa69df0 (patch)
tree053350f3dd7186759ced487ce470841c3bfb1030 /drivers/usb/storage/transport.c
parent3af51ac9c0889a188aaa3defe5134ef97c80d7c5 (diff)
usb-storage: redo incorrect reads
Some USB mass-storage devices have bugs that cause them not to handle the first READ(10) command they receive correctly. The Corsair Padlock v2 returns completely bogus data for its first read (possibly it returns the data in encrypted form even though the device is supposed to be unlocked). The Feiya SD/SDHC card reader fails to complete the first READ(10) command after it is plugged in or after a new card is inserted, returning a status code that indicates it thinks the command was invalid, which prevents the kernel from retrying the read. Since the first read of a new device or a new medium is for the partition sector, the kernel is unable to retrieve the device's partition table. Users have to manually issue an "hdparm -z" or "blockdev --rereadpt" command before they can access the device. This patch (as1470) works around the problem. It adds a new quirk flag, US_FL_INVALID_READ10, indicating that the first READ(10) should always be retried immediately, as should any failing READ(10) commands (provided the preceding READ(10) command succeeded, to avoid getting stuck in a loop). The patch also adds appropriate unusual_devs entries containing the new flag. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Tested-by: Sven Geggus <sven-usbst@geggus.net> Tested-by: Paul Hartman <paul.hartman+linux@gmail.com> CC: Matthew Dharm <mdharm-usb@one-eyed-alien.net> CC: <stable@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/storage/transport.c')
-rw-r--r--drivers/usb/storage/transport.c29
1 files changed, 29 insertions, 0 deletions
diff --git a/drivers/usb/storage/transport.c b/drivers/usb/storage/transport.c
index 00418995d8e9..e8ae21b2d387 100644
--- a/drivers/usb/storage/transport.c
+++ b/drivers/usb/storage/transport.c
@@ -819,6 +819,35 @@ Retry_Sense:
}
}
+ /*
+ * Some devices don't work or return incorrect data the first
+ * time they get a READ(10) command, or for the first READ(10)
+ * after a media change. If the INITIAL_READ10 flag is set,
+ * keep track of whether READ(10) commands succeed. If the
+ * previous one succeeded and this one failed, set the REDO_READ10
+ * flag to force a retry.
+ */
+ if (unlikely((us->fflags & US_FL_INITIAL_READ10) &&
+ srb->cmnd[0] == READ_10)) {
+ if (srb->result == SAM_STAT_GOOD) {
+ set_bit(US_FLIDX_READ10_WORKED, &us->dflags);
+ } else if (test_bit(US_FLIDX_READ10_WORKED, &us->dflags)) {
+ clear_bit(US_FLIDX_READ10_WORKED, &us->dflags);
+ set_bit(US_FLIDX_REDO_READ10, &us->dflags);
+ }
+
+ /*
+ * Next, if the REDO_READ10 flag is set, return a result
+ * code that will cause the SCSI core to retry the READ(10)
+ * command immediately.
+ */
+ if (test_bit(US_FLIDX_REDO_READ10, &us->dflags)) {
+ clear_bit(US_FLIDX_REDO_READ10, &us->dflags);
+ srb->result = DID_IMM_RETRY << 16;
+ srb->sense_buffer[0] = 0;
+ }
+ }
+
/* Did we transfer less than the minimum amount required? */
if ((srb->result == SAM_STAT_GOOD || srb->sense_buffer[2] == 0) &&
scsi_bufflen(srb) - scsi_get_resid(srb) < srb->underflow)