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SubjectRE: [PATCH 03/10] PCI: AMD SATA IDE mode quirk
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> On Thu, Feb 21, 2008 at 03:47:33PM -0800, Greg Kroah-Hartman wrote:
> > +static void __devinit quirk_amd_ide_mode(struct pci_dev *pdev)
> > {
> > - /* set sb600 sata to ahci mode */
> > - if ((pdev->class >> 8) == PCI_CLASS_STORAGE_IDE) {
> > - u8 tmp;
> > + /* set sb600/sb700/sb800 sata to ahci mode */
> > + u8 tmp;
> >
> > + pci_read_config_byte(pdev, PCI_CLASS_DEVICE, &tmp);
> > + if (tmp == 0x01) {
> > pci_read_config_byte(pdev, 0x40, &tmp);
>
> This seems like a dis-improvement. Why are we reading a
> config byte for something we already have in the pci_dev?
> Why are we now checking against 0x01 instead of a symbolic
> constant? Why are we no longer checking that this is
> PCI_BASE_CLASS_STORAGE?
It is a quirk. In pci_ids.h did have PCI_CLASS_STORAGE_IDE
and PCI_BASE_CLASS_STORAGE, these can not represent
the right situation we want to check. 0x01 represents
PCI_CLASS_STORAGE_IDE last 2 bit. Also because it
is a quirk, I do not think we need to change pci_ids.h. So 0x01
used.
> > -DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ATI,
> > PCI_DEVICE_ID_ATI_IXP600_SATA, quirk_sb600_sata);
> > -DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ATI,
> > PCI_DEVICE_ID_ATI_IXP700_SATA, quirk_sb600_sata);
> > +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ATI,
> > +PCI_DEVICE_ID_ATI_IXP600_SATA, quirk_amd_ide_mode);
> > +DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_ATI,
> > +PCI_DEVICE_ID_ATI_IXP600_SATA, quirk_amd_ide_mode);
> > +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ATI,
> > +PCI_DEVICE_ID_ATI_IXP700_SATA, quirk_amd_ide_mode);
> > +DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_ATI,
> > +PCI_DEVICE_ID_ATI_IXP700_SATA, quirk_amd_ide_mode);
>
> Nothing in the changelog entry suggests why we now need
> FIXUP_RESUME entries when we didn't before.
>
PCI configuration space will be changed by BIOS and then in pci
init and restore. So resume also needed.
> --
> Intel are signing my paycheques ... these opinions are still
> mine "Bill, look, we understand that you're interested in
> selling us this operating system, but compare it to ours. We
> can't possibly take such a retrograde step."
>
>



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