tree 2edbaf46167c86faad6b7645f3d3d2ef52bba84a
parent da0e21d3fa2340114fe24821718a1b57123e4664
author Tejun Heo <tj@kernel.org> 1217488174 +0900
committer Jeff Garzik <jgarzik@redhat.com> 1219385986 -0400

libata: restore SControl on detach

Save SControl during probing and restore it on detach.  This prevents
adjustments made by libata drivers to seep into the next driver which
gets attached (be it a libata one or not).

It's not clear whether SControl also needs to be restored on suspend.
The next system to have control (ACPI or kexec'd kernel) would
probably like to see the original SControl value but there's no
guarantee that a link is gonna keep working after SControl is adjusted
without a reset and adding a reset and modified recovery cycle soley
for this is an overkill.  For now, do it only for detach.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>