Re: [PATCH #upstream 2/2] libata-eh: clear UNIT ATTENTION after reset

[Jeff Garzik <jeff@garzik.org>]

Tejun Heo wrote:
> Resets make ATAPI devices raise UNIT ATTENTION which fails the next
> command.  As resets can happen asynchronously for unrelated reasons,
> this sometimes disrupts innocent users.  For example, reading DVD
> fails after the system wakes up from suspend or the other device
> sharing the channel went through bus error.
> 
> Clearing UA has some problems as it might clear UA which the userland
> needs to know about.  However, UA after resets can only be about the
> reset itself and benefits of clearing it overweights cons.  Missing UA
> can only delay failure to one of the following commands anyway.  For
> example, timeout while burning is in progress will trigger reset and
> reset the device state and probably corrupt the burning run.  Although
> the userland application won't get the UA, its pending writes will
> fail.
> 
> Signed-off-by: Tejun Heo <htejun@gmail.com>
> ---
>  drivers/ata/libata-eh.c |  105 +++++++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 99 insertions(+), 6 deletions(-)

ACK, but does not apply to #upstream