[PATCH 3.14 14/33] SCSI: sd: dont fail if the device doesnt recognize SYNCHRONIZE CACHE

Greg Kroah-Hartman
2014-04-24T22:38:46Z

From: Alan Stern <stern@rowland.harvard.edu>

commit 7aae51347b21eb738dc1981df1365b57a6c5ee4e upstream.

Evidently some wacky USB-ATA bridges don't recognize the SYNCHRONIZE
CACHE command, as shown in this email thread:

http://marc.info/?t=138978356200002&r=1&w=2

The fact that we can't tell them to drain their caches shouldn't
prevent the system from going into suspend. Therefore sd_sync_cache()
shouldn't return an error if the device replies with an Invalid
Command ASC.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Sven Neumann <s.neumann@raumfeld.com>
Tested-by: Daniel Mack <zonque@gmail.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/scsi/sd.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1463,8 +1463,8 @@ static int sd_sync_cache(struct scsi_dis
sd_print_sense_hdr(sdkp, &sshdr);
/* we need to evaluate the error return */
if (scsi_sense_valid(&sshdr) &&
- /* 0x3a is medium not present */
- sshdr.asc == 0x3a)
+ (sshdr.asc == 0x3a || /* medium not present */
+ sshdr.asc == 0x20)) /* invalid command */
/* this is no error here */
return 0;