Re: [PATCH #upstream-fixes] libata: don't normalize UNKNOWN to NONE after reset

[Jeff Garzik <jeff@garzik.org>]

Tejun Heo wrote:
> After non-classifying reset, ehc->classes[] could contain
> ATA_DEV_UNKNOWN which used to be normalized to ATA_DEV_NONE for
> consistency.  However, this causes unfortunate side effect for drivers
> which have non-classifying hardresets (e.g. sata_nv) by making
> hardreset report ATA_DEV_NONE for non-classifying resets and thus
> makes EH believe that the port is unoccupied and recovery can be
> skipped.  The end result is that after a device is swapped with
> another one, the new device isn't attached after the old one is
> detached.
> 
> This patch makes ata_eh_reset() not normalize UNKNOWN to NONE after
> non-classifying resets.  This fixes the above problem.  As UNKNOWN and
> NONE are handled differently by only EH hotplug logic, this doesn't
> cause other behavior changes.
> 
> Signed-off-by: Tejun Heo <htejun@gmail.com>
> Cc: Robert Hancock <hancockr@shaw.ca>
> ---
> Robert, missing new device was a bug in core EH logic not sata_nv.
> BTW, I did quite a few hotplug tests with adma=0 and it works just
> fine.  No lock up.
> 
>  drivers/ata/libata-eh.c |    4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)

applied