PCI fixup for old NCR 53C810 SCSI chips, kernel 2.4.18

This patch fixes a problem which prevents any version of the 2.4 kernel running on DECpc XL systems (from c. 1993). On that system, the NCR 53C810 SCSI subsystem integrated on the motherboard does not have a PCI class code, which breaks PCI resource allocation in all 2.4 kernels. The symptom is "resource collisions" reported for the SCSI device:

PCI: Device 00:01.0 not available because of resource collisions

These systems typically only have SCSI disks so the 2.4 kernel cannot be booted.

If you are running an earlier kernel and want to know if you will have this problem when upgrading, use lspci -vvv and look for output similar to this:

00:01.0 Non-VGA unclassified device: Symbios Logic Inc. (formerly NCR) 53c810 (rev 01)
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR- FastB2B-
Status: Cap- 66Mhz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort-
<TAbort- <MAbort- >SERR- <PERR-
Latency: 4 set
Interrupt: pin A routed to IRQ 11
Region 0: I/O ports at d000

If the listing says "Non-VGA unclassified device" for the 53c810, it will not work with the 2.4 kernel.

The workround is to add fixup code for this device in arch/i386/kernel/pci-pc.c. The patch is small and is included below. I would appreciate anyone who uses NCR 53c810-based SCSI devices testing this patch to make sure it doesn't break any other configurations. Graham Cobb

@@ -1058,6 +1058,18 @@
        d->resource[i].flags |= PCI_BASE_ADDRESS_SPACE_IO;

}

+static void __devinit pci_fixup_ncr53c810(struct pci_dev *d) +{
+ /*

+     * NCR 53C810 returns class code 0 (at least on some systems).
+     * Fix class to be PCI_CLASS_STORAGE_SCSI
+     */

+ if (!d->class) {
+ printk("PCI: fixing NCR 53C810 class code for %s\n", d->slot_name);
+ d->class = PCI_CLASS_STORAGE_SCSI << 8;
+ }
+}
+
static void __devinit pci_fixup_ide_bases(struct pci_dev *d)

{
    int i;

@@ -1148,6 +1160,7 @@
{ PCI_FIXUP_HEADER, PCI_VENDOR_ID_VIA,
PCI_DEVICE_ID_VIA_8622, pci_fixup_via_northbridge_bug },
{ PCI_FIXUP_HEADER, PCI_VENDOR_ID_VIA,
PCI_DEVICE_ID_VIA_8361, pci_fixup_via_northbridge_bug },
{ PCI_FIXUP_HEADER, PCI_VENDOR_ID_VIA,
PCI_DEVICE_ID_VIA_8367_0, pci_fixup_via_northbridge_bug },
+ { PCI_FIXUP_HEADER, PCI_VENDOR_ID_NCR, PCI_DEVICE_ID_NCR_53C810, pci_fixup_ncr53c810 },

    { 0 }
};

This problem seems not to be limited to ia32: on my DEC UDB AXP-box (on which I never tried 2.4.x so far), lspci shows:

| 00:06.0 Non-VGA unclassified device: Symbios Logic Inc. (formerly NCR) 53c810 (rev 01)
|	Flags: bus master, medium devsel, latency 255, IRQ 11
|	I/O ports at 8000
|	Memory at 0000000004200000 (32-bit, non-prefetchable)

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]

In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds