From: Namjae Jeon Date: Sun, 8 Jul 2012 03:05:08 +0000 (-0400) Subject: scsi: set to WCE if usb cache quirk is present. X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=7620c687429553d469afb699565054748d74b81f;p=deliverable%2Flinux.git 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 Signed-off-by: Pankaj Kumar Signed-off-by: Amit Sahrawat Cc: Alan Stern Cc: James Bottomley Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 6f72b80121a0..4225064db797 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 ba9698852321..6d65b55d47af 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 */