2012-06-10 01:30:41

by Namjae Jeon

Subject: [PATCH v3 2/4] usb: storage: add support for write cache quirk on usb hdd

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 <[email protected]>
Signed-off-by: Pankaj Kumar <[email protected]>
Signed-off-by: Amit Sahrawat <[email protected]>
---
drivers/usb/storage/scsiglue.c | 5 +++++
drivers/usb/storage/usb.c | 5 ++++-
include/linux/usb_usual.h | 4 +++-
3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c
index a324a5d..fe42547 100644
--- a/drivers/usb/storage/scsiglue.c
+++ b/drivers/usb/storage/scsiglue.c
@@ -230,6 +230,11 @@ 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
diff --git a/drivers/usb/storage/usb.c b/drivers/usb/storage/usb.c
index e23c30a..d012fe4 100644
--- a/drivers/usb/storage/usb.c
+++ b/drivers/usb/storage/usb.c
@@ -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;
diff --git a/include/linux/usb_usual.h b/include/linux/usb_usual.h
index 17df360..96fc152 100644
--- a/include/linux/usb_usual.h
+++ b/include/linux/usb_usual.h
@@ -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 };
--
1.7.9.5

2012-06-10 17:36:55

by Alan Stern

Subject: Re: [PATCH v3 2/4] usb: storage: add support for write cache quirk on usb hdd

On Sat, 9 Jun 2012, Namjae Jeon wrote:

> 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.

> --- a/include/linux/usb_usual.h
> +++ b/include/linux/usb_usual.h
> @@ -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 */

The documentation for the new flag should be added in the same patch
along with the flag itself. There's no reason to have separate
patches.

Alan Stern

2012-06-10 23:30:05

by Namjae Jeon

Subject: Re: [PATCH v3 2/4] usb: storage: add support for write cache quirk on usb hdd

2012/6/11, Alan Stern <[email protected]>:
> On Sat, 9 Jun 2012, Namjae Jeon wrote:
>
>> 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.
>
>> --- a/include/linux/usb_usual.h
>> +++ b/include/linux/usb_usual.h
>> @@ -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 */
>
> The documentation for the new flag should be added in the same patch
> along with the flag itself. There's no reason to have separate
> patches.
Hi. Alan.
Okay, I see. I will merge documentation patch with this patch.
Thank you.

>
> Alan Stern
>
>