On Wed, 11 Jan 2017, Pali Rohár wrote: > On Tuesday 10 January 2017 15:29:23 Alan Stern wrote: > > > Tom Yan wrote that smartctl/hdparm "works" because they use the SCSI ATA > > > PASSTHROUGH command. It is not an option for kernel? > > > > No, because many devices do not implement SCSI ATA PASSTHROUGH. > > (Consider devices whose underlying technology does not use ATA or SATA, > > for example.) And some of the ones that don't implement it will die if > > you try to send them an ATA PASSTHROUGH command. > > It is not possible to detect if underlaying device is ATA? I don't know any reliable way to do it. Besides, even if the device is ATA, you're still out of luck if the USB-SATA bridge doesn't support ATA PASSTHROUGH. > > You have to understand that consumer USB storage really is very > > low quality in many cases. Vendors aim for low cost rather than high > > reliability or correctness. > > Understood. But lot of distributions call hdparm for inserted disks and > also set some APM (or at least check it)... That means there is already > some way how to deal with these problems (in userspace). Maybe. Or maybe users simply don't use hdparm if it causes problems for them. You don't have a similar option with the kernel. Alan Stern -- 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
