Re: [PATCH 1/3] scsi: set to WCE if usb cache quirk is present.

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On 06-06-2012 16:20, Namjae Jeon wrote:

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@xxxxxxxxxxx>
Signed-off-by: Pankaj Kumar<>
Signed-off-by: Amit Sahrawat<a.sahrawat@xxxxxxxxxxx>
  drivers/scsi/sd.c          |    9 +++++++--
  include/scsi/scsi_device.h |    1 +
  2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 6f0a4c6..33faf6d 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2259,8 +2259,13 @@ bad_sense:
  		sd_printk(KERN_ERR, sdkp, "Asking for cache data failed\n");

-	sd_printk(KERN_ERR, sdkp, "Assuming drive cache: write through\n");
-	sdkp->WCE = 0;
+	if (sdp->wce_quirk) {
+		sdkp->WCE = 1;
+		sd_printk(KERN_NOTICE, sdkp, "Assuming drive cache write back\n");

   You forgot colon after "cache".

+	} else {
+		sd_printk(KERN_ERR, sdkp, "Assuming drive cache: write through\n");
+		sdkp->WCE = 0;

It makes sense to do assignments and printk() in the same order in both branches.

+	}
  	sdkp->RCD = 0;
  	sdkp->DPOFUA = 0;

WBR, Sergei
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