On Wed, Oct 5, 2011 at 10:54 PM, James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> wrote: > On Wed, 2011-10-05 at 22:29 +0530, Amit Sahrawat wrote: >> Can anyone suggest what is the way ahead to detect the presence of >> Write Cache in these kind of USB HDD and proceed accordingly by >> assigning proper flushing method. >> Please share some opinions on this. > > We're a bit out of ideas. We've already established that we do exactly > what windows does in this situation, which is usually what we aim for. > Realistically, if the disks lie how do we know when not to believe them? I never knew this could turn out to be an issue with such history. But atleast debugging helped in diagnosis. > > The best we could probably offer is an interface to turn on the WCE bit > in software (technically, you can do this today > in /scsi/class/scsi_disk/<disk>/cache_type, it's just that it will try > to commit the change as a MODE_SELECT which will presumably fail). Thanks James, is this related with SCSI command MODE_SELECT? and this is to be passed when there is some failure? or simply doing an "echo <value>" to /scsi/class/scsi_disk/<disk>/cache_type? can you please elaborate a little > > James > Thanks & Regards, Amit Sahrawat -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
