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[SCSI] usb-storage: add support for write cache quirk

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Add support for write cache quirk on usb hdd. scsi driver will be set to wce
by detecting write cache quirk in quirk list when plugging usb hdd.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Pankaj Kumar <pankaj.km@samsung.com>
Signed-off-by: Amit Sahrawat <a.sahrawat@samsung.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This commit is contained in:
Namjae Jeon 2012-07-07 23:05:28 -04:00 committed by James Bottomley
parent b81478d82e
commit eaa05dfcdb
4 changed files with 14 additions and 2 deletions
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2
Documentation/kernel-parameters.txt
View File

@ -2932,6 +2932,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
initial READ(10) command);
o = CAPACITY_OK (accept the capacity
reported by the device);
p = WRITE_CACHE (the device cache is ON
by default);
r = IGNORE_RESIDUE (the device reports
bogus residue values);
s = SINGLE_LUN (the device has only one

5
drivers/usb/storage/scsiglue.c
View File

@ -236,6 +236,11 @@ static int slave_configure(struct scsi_device *sdev)
US_FL_SCM_MULT_TARG)) &&
us->protocol == USB_PR_BULK)
us->use_last_sector_hacks = 1;
/* Check if write cache default on flag is set or not */
if (us->fflags & US_FL_WRITE_CACHE)
sdev->wce_default_on = 1;
} else {
/* Non-disk-type devices don't need to blacklist any pages

5
drivers/usb/storage/usb.c
View File

@ -473,7 +473,7 @@ static void adjust_quirks(struct us_data *us)
US_FL_CAPACITY_OK | US_FL_IGNORE_RESIDUE |
US_FL_SINGLE_LUN | US_FL_NO_WP_DETECT |
US_FL_NO_READ_DISC_INFO | US_FL_NO_READ_CAPACITY_16 |
US_FL_INITIAL_READ10);
US_FL_INITIAL_READ10 | US_FL_WRITE_CACHE);
p = quirks;
while (*p) {
@ -529,6 +529,9 @@ static void adjust_quirks(struct us_data *us)
case 'o':
f |= US_FL_CAPACITY_OK;
break;
case 'p':
f |= US_FL_WRITE_CACHE;
break;
case 'r':
f |= US_FL_IGNORE_RESIDUE;
break;

4
include/linux/usb_usual.h
View File

@ -64,7 +64,9 @@
US_FLAG(NO_READ_CAPACITY_16, 0x00080000) \
/* cannot handle READ_CAPACITY_16 */ \
US_FLAG(INITIAL_READ10, 0x00100000) \
/* Initial READ(10) (and others) must be retried */
/* Initial READ(10) (and others) must be retried */ \
US_FLAG(WRITE_CACHE, 0x00200000) \
/* Write Cache status is not available */
#define US_FLAG(name, value) US_FL_##name = value ,
enum { US_DO_ALL_FLAGS };