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authorAlan Stern <stern@rowland.harvard.edu>2011-06-07 11:35:52 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2011-06-07 09:05:42 -0700
commit21c13a4f7bc185552c4b402b792c3bbb9aa69df0 (patch)
tree053350f3dd7186759ced487ce470841c3bfb1030 /Documentation
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 'Documentation')
-rw-r--r--Documentation/kernel-parameters.txt2
1 files changed, 2 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index d9a203b058f1..fd248a318211 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2598,6 +2598,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
unlock ejectable media);
m = MAX_SECTORS_64 (don't transfer more
than 64 sectors = 32 KB at a time);
+ n = INITIAL_READ10 (force a retry of the
+ initial READ(10) command);
o = CAPACITY_OK (accept the capacity
reported by the device);
r = IGNORE_RESIDUE (the device reports