Re: PCI: Add ALI M5229 comaptibility mode quirk

[Ben Dooks <ben-linux@fluff.org>]

On Fri, Sep 12, 2008 at 06:33:40AM -0600, Matthew Wilcox wrote:
> On Fri, Sep 12, 2008 at 12:22:52PM +0100, Ben Dooks wrote:
> > The libata driver will not work with an M5229 set into native IDE
> > mode (the old drivers/pci one does) if the M5229 does not provide
> > it's own IRQ.
> > 
> > The M5229 implementation embedded into the ALI M1543 uses the
> > M1543's ISA PIC to provide the interrupts and thus does not have
> > an valid PCI IRQ set. This quirk detects the abscence of IRQ and
> > sets the M5229 back into compatibility mode to use IRQs 14 and 15
> > so that libata works correctly.
> > 
> > Note, I belive that the check for an valid interrupt line is
> > correct, I only have an M5229 in an ALI M1543 to check this
> > on. It would be useful to confirm that a M5229 with an valid IRQ
> > does not trigger this quirk.
> 
> Why does this need to be a quirk rather than something in the libata ALi
> driver?

The short answer is that "Alan Cox says not in libata", the longer
one can be found:

http://www.archivum.info/linux-ide@vger.kernel.org/2008-07/msg00410.html
 
> > Signed-off-by: Ben Dooks <ben-linux@fluff.org>
> > 
> > Index: linux-2.6.27-rc6-cats1/drivers/pci/quirks.c
> > ===================================================================
> > --- linux-2.6.27-rc6-cats1.orig/drivers/pci/quirks.c	2008-09-11 11:26:35.000000000 +0100
> > +++ linux-2.6.27-rc6-cats1/drivers/pci/quirks.c	2008-09-12 12:18:05.000000000 +0100
> > @@ -905,6 +905,34 @@ static void __devinit quirk_svwks_csb5id
> >  }
> >  DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SERVERWORKS, PCI_DEVICE_ID_SERVERWORKS_CSB5IDE, quirk_svwks_csb5ide);
> >  
> > +/* Some systems set the ALI M5229 in the ALI M1543 bridge to native mode,
> > + * which cannot be supported by the pata_ali.c driver (the old drivers/ide
> > + * makes a compatibility effort to change the IDE interrupts).
> > + */
> > +static void __devinit quirk_ali_ide_compatibility(struct pci_dev *pdev)
> > +{
> > +	u8 tmp;
> > +
> > +	/* pdev->irq and pdev->pin have yet to be initialised, so check
> > +	 * by reading from the configuration header to see if we've got
> > +	 * a valid interrupt line. */
> > +
> > +	pci_read_config_byte(pdev, PCI_INTERRUPT_LINE, &tmp);
> > +	if (tmp != 0xff)
> > +		return;
> > +
> > +	pci_read_config_byte(pdev, PCI_CLASS_PROG, &tmp);
> > +	if (tmp & 0x5) {
> > +		dev_info(&pdev->dev, "quirk: changing to IDE compatibility mode\n");
> > +
> > +		tmp &= ~0x05;
> > +		pdev->class &= ~0x05;
> > +		pci_write_config_byte(pdev, PCI_CLASS_PROG, tmp);
> > +	}
> > +}
> > +
> > +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M5229, quirk_ali_ide_compatibility);
> > +
> >  /*
> >   *	Intel 82801CAM ICH3-M datasheet says IDE modes must be the same
> >   */
> > 
> > -- 
> > Ben (ben@fluff.org, http://www.fluff.org/)
> > 
> >   'a smiley only costs 4 bytes'
> > --
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> 
> -- 
> Matthew Wilcox				Intel Open Source Technology Centre
> "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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-- 
-- 
Ben

Q:      What's a light-year?
A:      One-third less calories than a regular year.