Re: [PATCH] ata: make DVD drive recognisable on systems with Intel Sandybridge CPT chipset

[Tejun Heo <htejun@xxxxxxxxx>]

Hello,

(cc'ing Jeff)

On Thu, Sep 22, 2011 at 09:55:12AM +0800, ming.lei@xxxxxxxxxxxxx wrote:
> From: Ming Lei <ming.lei@xxxxxxxxxxxxx>
> 
> This quirk patch fixes one kind of bug inside Intel Sandybridge CPT
> chipset, see reports from
> 
> 	https://bugzilla.kernel.org/show_bug.cgi?id=40592.
> 
> Many guys also have reported the problem before:
> 
> 	https://bugs.launchpad.net/bugs/737388
> 	https://bugs.launchpad.net/bugs/794642
> 	......
> 
> With help from Tejun, the problem is found to be caused by 32bit PIO
> mode, so introduce the quirk patch to disable 32bit PIO on SATA piix
> for Sandybridge CPT chipset.

Have we successfully localized the problem to SNB?  If so, great.

>  static struct ata_port_operations piix_vmw_ops = {
> @@ -1585,6 +1586,15 @@ static int __devinit piix_init_one(struct pci_dev *pdev,
>  				"on poweroff and hibernation\n");
>  	}
>  
> +	/*
> +	 * Sandybridge chipset H61/P67/H67 have broken 32 mode up to now
> +	 * see https://bugzilla.kernel.org/show_bug.cgi?id=40592
> +	 */
> +	if (pdev->vendor == PCI_VENDOR_ID_INTEL && pdev->device == 0x1c00)
> +		piix_sata_ops.inherits = &ata_bmdma_port_ops;
> +	else
> +		piix_sata_ops.inherits = &ata_bmdma32_port_ops;
> +

No, this wouldn't work.  Ops inheritance isn't dynamic.

Please define a separate ata_port_operations for controller which
require 16bit PIO - piix_pata16_ops, create a new controller id (say,
ich_snb_pata), add an accompanying port_info entry and device_id
entry.

Thank you.

-- 
tejun
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