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SubjectRe: [PATCH] Add SATA device to VIA IRQ quirk fixup list
On Fri, 14 Jul 2006 13:15:54 +0100 Daniel Drake wrote:

> Jeff Garzik wrote:
> > Same rationale, but the VIA SATA PCI ID had been submitted before, as
> > well...
>
> OK. So what's the realistic solution?
>
> The best I can think of is something like this (see attachment).
>
> It's not perfect, because if someone inserts a VIA PCI card into a
> VIA-based motherboard, the quirk will also run on that VIA PCI card.

I still do not understand what will break in this case - won't the
external device just ignore the value which the quirk will write into
its PCI_INTERRUPT_LINE register?

Can someone point me at examples of breakage caused by the original
quirk matching non-builtin devices? The examples of breakage caused by
missing devices are everywhere now :(

> Is there a way we can realistically say "this is an on-board device" vs
> "this is a PCI card"?

I thought about limiting to some range of PCI device numbers on the same
bus as the VIA southbridge, but this range does not seem to be
well-defined even for V-Link devices, and old PCI chips like 82C686 had
an external IDSEL# input and could end up on any device number (they had
only a single multifunction PCI device, however).

> This is untested but I'll happily test and work on it further if it
> doesn't get shot down :)
> I have only added the southbridges for my own hardware and the one
> listed on the Gentoo bug. I guess there will be more. I also wonder if
> listing the southbridges is the most sensible approach or if other
> devices (e.g. the host bridge at 00:00.0) would be more appropriate?

Using the host bridge as a trigger definitely does not look correct
(e.g., 82C686 looks like a normal PCI device and could be used in
systems with non-VIA host bridges).

> Daniel

> [PATCH] Add SATA device to VIA IRQ quirk fixup list
>
> Gentoo users at http://bugs.gentoo.org/138036 reported a 2.6.16.17 regression:
> new kernels will not boot their system from their VIA SATA hardware.
>
> The solution is just to add the SATA device to the fixup list.
> This should also fix the same problem reported by Scott J. Harmon on LKML.

Now this changelog is obviously wrong...

> Signed-off-by: Daniel Drake <dsd@gentoo.org>
>
> Index: linux/drivers/pci/quirks.c
> ===================================================================
> --- linux.orig/drivers/pci/quirks.c
> +++ linux/drivers/pci/quirks.c
> @@ -648,10 +648,31 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_V
> * Some of the on-chip devices are actually '586 devices' so they are
> * listed here.
> */
> +
> +static int via_irq_fixup_needed = -1;
> +
> +/*
> + * As some VIA hardware is available in PCI-card form, we need to restrict
> + * this quirk to VIA PCI hardware built onto VIA-based motherboards only.
> + * This table lists southbridges on motherboards where this quirk needs to
> + * be run.
> + */
> +static const struct pci_device_id via_irq_fixup_tbl[] = {
> + { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8233A) },
> + { PCI_DEVICE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8237) },

This table is even more incomplete than the original. I found these ISA
bridge IDs from VIA in my copy of pci.ids:

0586 VT82C586/A/B PCI-to-ISA [Apollo VP]
0596 VT82C596 ISA [Mobile South]
0686 VT82C686 [Apollo Super South]
3074 VT8233 PCI to ISA Bridge
3109 VT8233C PCI to ISA Bridge
3147 VT8233A ISA Bridge
3177 VT8235 ISA Bridge
3227 VT8237 ISA bridge [KT600/K8T800/K8T890 South]
3287 VT8251 PCI to ISA Bridge
3337 VT8237A PCI to ISA Bridge
8231 VT8231 [PCI-to-ISA Bridge]

The major problem with this approach is that this PCI ID list will
inevitably get stale, and there will be no easy way to boot the kernel
on a newer system. And there is no sign that VIA turns away from their
habit of using PCI_INTERRUPT_LINE for IRQ routing...

However, what about triggering the quirk on any ISA bridge from VIA:

{
.vendor = PCI_VENDOR_ID_VIA,
.device = PCI_ANY_ID,
.subvendor = PCI_ANY_ID,
.subdevice = PCI_ANY_ID,
.class = PCI_CLASS_BRIDGE_ISA << 8,
.class_mask = 0xffff00,
}
> + { 0, },
> +};
> +
> static void quirk_via_irq(struct pci_dev *dev)
> {
> u8 irq, new_irq;
>
> + if (via_irq_fixup_needed == -1)
> + via_irq_fixup_needed = pci_dev_present(via_irq_fixup_tbl);
> +
> + if (!via_irq_fixup_needed)
> + return;
> +
> new_irq = dev->irq & 0xf;
> pci_read_config_byte(dev, PCI_INTERRUPT_LINE, &irq);
> if (new_irq != irq) {
> @@ -661,13 +682,7 @@ static void quirk_via_irq(struct pci_dev
> pci_write_config_byte(dev, PCI_INTERRUPT_LINE, new_irq);
> }
> }
> -DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_0, quirk_via_irq);
> -DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_1, quirk_via_irq);
> -DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_2, quirk_via_irq);
> -DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_3, quirk_via_irq);
> -DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C686, quirk_via_irq);
> -DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C686_4, quirk_via_irq);
> -DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C686_5, quirk_via_irq);
> +DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_VIA, PCI_ANY_ID, quirk_via_irq);
>
> /*
> * VIA VT82C598 has its device ID settable and many BIOSes
>
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