Re: [lm-sensors] PCI: Quirk for hwmon access on MSI MS-7031 board

[Jean Delvare <khali@linux-fr.org>]

Hi Matthew,

On Wed, 27 May 2009 09:44:31 -0600, Matthew Wilcox wrote:
> On Mon, May 25, 2009 at 10:06:52PM +0200, Jean Delvare wrote:
> > The MSI MS-7031 is based on an ATI IXP300 south bridge. On this south
> > bridge, accessible I/O ports must be enabled explicitly. Unfortunately
> > the BIOS forgets to enable access to the hardware monitoring chip I/O
> > ports, so hardware monitoring fails.
> > 
> > Add a quirk enabling access to the required ports (0x295-0x296). This
> > is exactly what MSI's own hardware monitoring application is doing, so
> > it has to be the right way.
> 
> > +#if defined CONFIG_X86 && (defined CONFIG_HWMON || defined CONFIG_HWMON_MODULE)
> 
> I don't like this.  It goes against the principle that enabling a module
> shouldn't cause the base kernel to get rebuilt. Is there a reason that
> the hardware monitoring code can't contain this quirk instead of the
> generic PCI code?

No reason other than the fact that putting it in pci/quirks.c was
easier. I can certainly move the quirk to hwmon/hwmon.c, but as far as
I can see you have the exact same problem there: enabling or disabling
PCI support will cause the base hwmon module to be rebuilt. If hwmon is
built into the kernel then you have to relink the kernel.

> > +/* Open access to 0x295-0x296 (hardware monitoring chip) on MSI MS-7031 */
> > +static void __devinit ati_ixp300_open_ioport(struct pci_dev *dev)
> > +{
> > +	u16 base;
> > +	u8 enable;
> > +
> > +	if (!(dev->subsystem_vendor = 0x1462 &&	/* MSI */
> > +	      dev->subsystem_device = 0x0031))		/* MS-7031 */
> > +		return;
> > +
> > +	pci_read_config_byte(dev, 0x48, &enable);
> > +	pci_read_config_word(dev, 0x64, &base);
> > +
> > +	if (base = 0 && !(enable & BIT(2))) {
> > +		dev_info(&dev->dev, "Opening wide generic port at 0x295\n");
> > +		pci_write_config_word(dev, 0x64, 0x295);
> > +		pci_write_config_byte(dev, 0x48, enable | BIT(2));
> > +	}
> > +}
> > +
> > +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ATI, 0x436c, ati_ixp300_open_ioport);
> > +#endif	/* CONFIG_X86 && CONFIG_HWMON */
> > +
> >  static void pci_do_fixups(struct pci_dev *dev, struct pci_fixup *f,
> >  			  struct pci_fixup *end)
> >  {

-- 
Jean Delvare

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