Paul Collins wrote:
> I just noticed that my optical drive no longer works with 2.6.25-rc9.
> It works with 2.6.24.3.  git bisect claims the culprit is
> c729072459446885c5c200137de1db32da5db4dc ("ata_piix: implement SIDPR SCR
> access").
> 
>   $ diff -u cd.{ok,no} | grep '^.ata'
>    ata_piix 0000:00:1f.2: version 2.12
>   -ata_piix 0000:00:1f.2: MAP [ P0 P2 P1 P3 ]
>   +ata_piix 0000:00:1f.2: MAP [ P0 P2 P1 P3 ]
>    ata1: SATA max UDMA/133 cmd 0x1f0 ctl 0x3f6 bmdma 0x20e0 irq 14
>    ata2: SATA max UDMA/133 cmd 0x170 ctl 0x376 bmdma 0x20e8 irq 15
>   +ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
>    ata1.00: ATA-7: SAMSUNG HD080HJ/P, ZH100-51, max UDMA/100
>    ata1.00: 156301488 sectors, multi 16: LBA48 
>    ata1.00: configured for UDMA/100
>   -ata2.00: ATAPI: HL-DT-ST RW/DVD GCC-H10N, 1.03, max UDMA/100
>   -ata2.00: configured for UDMA/100
>   +ata2: SATA link down (SStatus 611 SControl 300)

That's very strange.  The link is in slumber powersave mode.  I wonder 
how it got there.  Can you please try the attached patch and report 
resulting boot log?

-- 
tejun