| Message ID | yq18tw4rpsy.fsf@sermon.lab.mkp.net (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
On Wed, 2016-08-10 at 22:40 -0400, Martin K. Petersen wrote: > >>>>> "Oliver" == Oliver Neukum <oneukum@suse.com> writes: > > Oliver> Some SATA to USB bridges fail to cooperate with some drives > Oliver> resulting in no cache being present being reported to the > Oliver> host. That causes the host to skip sending a command to > Oliver> synchronize caches. That causes data loss when the drive is > Oliver> powered down. > > diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h > index a6c346d..392d166 100644 > --- a/include/scsi/scsi_device.h > +++ b/include/scsi/scsi_device.h > @@ -179,6 +179,7 @@ struct scsi_device { > 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 */ > + unsigned always_sync:1; /* synchronize cache in every case*/ > unsigned no_dif:1; /* T10 PI (DIF) should be disabled */ > unsigned broken_fua:1; /* Don't set FUA bit */ > unsigned lun_in_cdb:1; /* Store LUN bits in CDB[1] */ > > I must be missing something. How is always_sync different from just > setting wce_default_on? Hi, wce_default_on controls the default if the device provides no indication. The problem here is that the indication the device provides must be overridden, as they are false. Regards Oliver -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
>>>>> "Oliver" == Oliver Neukum <oneukum@suse.com> writes:
Oliver,
Oliver> wce_default_on controls the default if the device provides no
Oliver> indication. The problem here is that the indication the device
Oliver> provides must be overridden, as they are false.
Can't you just blacklist the mode select on the device in question?
Something like:
if (us->fflags & US_FL_ALWAYS_SYNC) {
sdev->skip_ms_page_3f = 1;
sdev->skip_ms_page_8 = 1;
sdev->wce_default_on = 1;
}
?
On Tue, 2016-08-16 at 00:44 -0400, Martin K. Petersen wrote: > >>>>> "Oliver" == Oliver Neukum <oneukum@suse.com> writes: > > Oliver, > > Oliver> wce_default_on controls the default if the device provides no > Oliver> indication. The problem here is that the indication the device > Oliver> provides must be overridden, as they are false. > > Can't you just blacklist the mode select on the device in question? > > Something like: > > if (us->fflags & US_FL_ALWAYS_SYNC) { > sdev->skip_ms_page_3f = 1; > sdev->skip_ms_page_8 = 1; > sdev->wce_default_on = 1; > } > > ? Hi, this looks like a workable option. I am preparing a patch. Regards Oliver -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h index a6c346d..392d166 100644 --- a/include/scsi/scsi_device.h +++ b/include/scsi/scsi_device.h @@ -179,6 +179,7 @@ struct scsi_device { 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 */ + unsigned always_sync:1; /* synchronize cache in every case*/ unsigned no_dif:1; /* T10 PI (DIF) should be disabled */ unsigned broken_fua:1; /* Don't set FUA bit */ unsigned lun_in_cdb:1; /* Store LUN bits in CDB[1] */
>>>>> "Oliver" == Oliver Neukum <oneukum@suse.com> writes: Oliver> Some SATA to USB bridges fail to cooperate with some drives Oliver> resulting in no cache being present being reported to the Oliver> host. That causes the host to skip sending a command to Oliver> synchronize caches. That causes data loss when the drive is Oliver> powered down. I must be missing something. How is always_sync different from just setting wce_default_on?