diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index a92c5ebf373e..c68634edd451 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -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 diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c index 11418da9bc09..a3d54366afcc 100644 --- a/drivers/usb/storage/scsiglue.c +++ b/drivers/usb/storage/scsiglue.c @@ -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 diff --git a/drivers/usb/storage/usb.c b/drivers/usb/storage/usb.c index e23c30ab66da..d012fe4329e7 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 17df3600bcef..e84e769aaddc 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 };