> >> > Not all of them safely, though. Many a drive will corrupt data if it
> >> > receives a command when not spinned up. You need to issue a wake command
> >> > first, which hdparm doesn't, it just leaves it to the kernel to issue a
> >> > read command or whatever to wake the drive ...
> >>
> >> Is this common disk bug, or are they permitted to behave like that?
> >
> >This behavior is permitted by the specification, as far as I know -
>
> Actually not. Have a look at page 36 of the current ATA6
> specification.
Good. So noflushd is safe.
Pavel
> If a disk has entered power state PM3:sleep, its interface is turned
> off! You no longer can issue any command except for a DEVICE RESET to
> this unit. A reset is required to initiate a state transition from
> PM3:sleep to PM2:standby (there are no other state transitions).
I do not think we are using PM3:sleep in noflushd, but we even
could. AFAICT, ide layer resets interface if it does not respond.
-- Casualities in World Trade Center: ~3k dead inside the building, cryptography in U.S.A. and free speech in Czech Republic. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/