Re: [PATCH 1/2] ahci: implement ata_save/restore_initial_config()

[Jeff Garzik <jeff@garzik.org>]

Tejun Heo wrote:
> There are several registers which describe how the controller is
> configured.  These registers are sometimes implemented as r/w
> registers which are configured by firmware and get cleared on
> controller reset or after suspend/resume cycle.  ahci saved and
> restored those values inside ahci_reset_controller() which is a bit
> messy and doesn't work over suspend/resume cycle.
> 
> This patch implements ahci_save/restore_initial_config().  The save
> function is called during driver initialization and saves cap and
> port_map to hpriv.  The restore function is called after the
> controller is reset to restore the initial values.
> 
> Sometimes the initial firmware values are inconsistent and need to be
> fixed up.  This is handled by ahci_save_initial_config().  For this,
> there are two versions of saved registers.  One to write back to the
> hardware register, the other to use during driver operation.  This is
> necessary to keep ahci's behavior unchanged (write back fixed up
> port_map while keeping cap as-is).
> 
> This patch makes ahci save the register values once before the first
> controller reset, not after it's been reset.  Also, the same stored
> values are used written back after each reset, so the register values
> are properly recovered after suspend/resume cycle.
> 
> Signed-off-by: Tejun Heo <htejun@gmail.com>
> ---
> Jeff, this is the save/restore separation patch as suggested.

applied 1-2