Re: [PATCH] libata: Use IGN_SIMPLEX for ALi

[Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>]

On Wednesday 13 May 2009 15:49:04 Alan Cox wrote:
> > [ Sigh, this issue seems to go back to:
> > 
> >   commit 669a5db411d85a14f86cd92bc16bf7ab5b8aa235
> >   Author: Jeff Garzik <jeff@garzik.org>
> >   Date:   Tue Aug 29 18:12:40 2006 -0400
> > 
> >     [libata] Add a bunch of PATA drivers. ]
> 
> No its quite recent actually - broke around 2.6.27
> 
> The libata drivers try and reset the simplex bits to check if a device is
> merely in simplex mode by configuration. Unfortunately on the ALi if you
> put the device into a power saving mode and bring it back the simplex
> bits get corrupted and the register becomes unwritable (even to restore)
> 
> Somewhere around 2.6.27 something started rudely dumping the device into
> power saving mode outside of the ATA layer on certain PCs.
> 
> So we switch to ignoring the bit in the first place on this chip.

Ok, thanks for explaining it.

BTW you may consider removing ata_pci_bmdma_clear_simplex() call
from ali_init_chipset() now (before somebody decides to fix the code
to check the former's function return value).