Re: [PATCH] ahci: ahci: implement workaround for ASUS P5W-DH Deluxe ahci_broken_hardreset(), take #2

[Jeff Garzik <jeff@garzik.org>]

Tejun Heo wrote:
> P5W-DH Deluxe has ICH9 which doesn't have PMP support but SIMG 4726
> hardwired to the second port of AHCI controller at PCI device 1f.2.
> The 4726 doesn't work as PMP but as a storage processor which can do
> hardware RAID on downstream ports.
> 
> When no device is attached to the downstream port of the 4726, pseudo
> ATA device for configuration appears.  Unfortunately, ATA emulation on
> the device is very lousy and causes long hang during boot.
> 
> This patch implements workaround for the board.  If the mainboard is
> P5W-DH Deluxe (matched using DMI), only hardreset is used on the
> second port of AHCI controller @ 1f.2 and the hardreset doesn't depend
> on receiving the first FIS and just proceed to IDENTIFY.
> 
> This workaround fixes bugzilla #8923.
> 
>   http://bugzilla.kernel.org/show_bug.cgi?id=8923
> 
> Signed-off-by: Tejun Heo <htejun@gmail.com>
> ---
> Okay, here's improved version.  p5wdh hardreset is sufficiently
> different from vt8251, so it now has its own hardreset and ops.  It
> now also has two secs + 150ms delay after hardreset so that devices
> which are slow to respond after hardreset don't fail.  Most devices
> will respond in time unless it's spinning up.  Spin up is handled by
> reset retrials.  Also, it sets BSY before initiating BSY and performs
> CLO afterward if BSY isn't cleared during the wait.
> 
> Change from the first take are minor but make the workaoround fit the
> problem better.  Tested on a setup which behaves the same way as
> P5W-DH (non-PMP capable ICH AHCI + SIMG 4726) with some number of
> harddrives and ATAPI devices.  Everything including hotplug works
> fine.
> 
>  drivers/ata/ahci.c |  144 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 144 insertions(+)

applied