From: Namjae Jeon <[email protected]> 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 <[email protected]> Signed-off-by: Pankaj Kumar <[email protected]> Signed-off-by: Amit Sahrawat <[email protected]> --- 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 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 b6cf0cf..61ff671 100644 --- a/include/scsi/scsi_device.h +++ b/include/scsi/scsi_device.h @@ -156,6 +156,7 @@ struct scsi_device { unsigned is_visible:1; /* is the device visible in sysfs */ unsigned can_power_off:1; /* Device supports runtime power off */ unsigned wakeup_by_user:1; /* user wakes up the ODD */ + 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 */ -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
