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authorNamjae Jeon <namjae.jeon@samsung.com>2012-07-07 23:05:08 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-07-16 16:43:49 -0700
commit7620c687429553d469afb699565054748d74b81f (patch)
tree5ee5d5e4ca5ed45c073434bf366ec41367f02ac7
parentb903bd69e3fa156598def8d6433dfe5352af8da3 (diff)
downloadop-kernel-dev-7620c687429553d469afb699565054748d74b81f.zip
op-kernel-dev-7620c687429553d469afb699565054748d74b81f.tar.gz
scsi: set to WCE if usb cache quirk is present.
Make use of USB quirk method to identify such HDD while reading the cache status in sd_probe(). If cache quirk is present for the HDD, lets assume that cache is enabled and make WCE bit equal to 1. 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> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/scsi/sd.c9
-rw-r--r--include/scsi/scsi_device.h1
2 files changed, 8 insertions, 2 deletions
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 6f72b80..4225064 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2261,8 +2261,13 @@ bad_sense:
sd_printk(KERN_ERR, sdkp, "Asking for cache data failed\n");
defaults:
- sd_printk(KERN_ERR, sdkp, "Assuming drive cache: write through\n");
- sdkp->WCE = 0;
+ if (sdp->wce_default_on) {
+ sd_printk(KERN_NOTICE, sdkp, "Assuming drive cache: write back\n");
+ sdkp->WCE = 1;
+ } else {
+ sd_printk(KERN_ERR, sdkp, "Assuming drive cache: write through\n");
+ sdkp->WCE = 0;
+ }
sdkp->RCD = 0;
sdkp->DPOFUA = 0;
}
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index ba96988..6d65b55 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -153,6 +153,7 @@ struct scsi_device {
unsigned no_read_capacity_16:1; /* Avoid READ_CAPACITY_16 cmds */
unsigned try_rc_10_first:1; /* Try READ_CAPACACITY_10 first */
unsigned is_visible:1; /* is the device visible in sysfs */
+ unsigned wce_default_on:1; /* Cache is ON by default */
DECLARE_BITMAP(supported_events, SDEV_EVT_MAXBITS); /* supported events */
struct list_head event_list; /* asserted events */
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