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VIA 82C686B SouthBridge fixup in linux/drivers/pci/quirks.c

PATCH Jeff S Wheeler 2 participants 2 messages Jun 30, 2001 PCI

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Jeff S Wheeler

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Hi, I am not subscribed to the list. Please CC me on replies.

The VIA686B SouthBridge bug workaround is not activated on motherboards which have a VIA 82C686B that needs fixing, but not a VIA NorthBridge. For example, my Asus A7M266 has an AMD 761 NorthBridge, and the table at the end of linux/drivers/pci/quirks.c thus does not attempt to apply the fix. Someone suggested a fix against 2.4.4 in this thread, however it has not all been fixed on 2.4.5 nor 2.4.5-ac22 (current, I believe).

Below is a patch to the __initdata table which causes the fix to be applied based on detection of the buggy SouthBridge, and *not* the NorthBridge which is commonly used with it. This is the correct behavior, and was suggested by someone during the thread I reference, however this aspect of the fix was overlooked.

http://mailman.real-time.com/pipermail/linux-kernel/Week-of-Mon-20010430/032
013.html

---
Jeff S Wheeler [email protected]
Software Development Five Elements, Inc

drivers/pci/quirks.c Fri Jun 29 20:58:14 2001 renamed from drivers/pci/quirks.c.orig Fri Jun 29 20:24:09 2001 +0 -0
@@ -358,7 +358,7 @@
        { PCI_FIXUP_FINAL,      PCI_VENDOR_ID_INTEL,

PCI_DEVICE_ID_INTEL_82443BX_2,  quirk_natoma },
        { PCI_FIXUP_FINAL,      PCI_VENDOR_ID_SI,
PCI_DEVICE_ID_SI_5597,          quirk_nopcipci },
        { PCI_FIXUP_FINAL,      PCI_VENDOR_ID_SI,
PCI_DEVICE_ID_SI_496,           quirk_nopcipci },
-       { PCI_FIXUP_FINAL,      PCI_VENDOR_ID_VIA,
PCI_DEVICE_ID_VIA_8363_0,       quirk_vialatency },
+       { PCI_FIXUP_FINAL,      PCI_VENDOR_ID_VIA,
PCI_DEVICE_ID_VIA_82C686,       quirk_vialatency },
        { PCI_FIXUP_FINAL,      PCI_VENDOR_ID_VIA,
PCI_DEVICE_ID_VIA_82C597_0,     quirk_viaetbf },
        { PCI_FIXUP_HEADER,     PCI_VENDOR_ID_VIA,
PCI_DEVICE_ID_VIA_82C597_0,     quirk_vt82c598_id },
        { PCI_FIXUP_HEADER,     PCI_VENDOR_ID_VIA,
PCI_DEVICE_ID_VIA_82C586_3,     quirk_vt82c586_acpi },
#1 lore raw
Quoted 7 lines · Jeff S Wheeler

The VIA686B SouthBridge bug workaround is not activated on motherboards which have a VIA 82C686B that needs fixing, but not a VIA NorthBridge. For

Below is a patch to the __initdata table which causes the fix to be applied based on detection of the buggy SouthBridge, and *not* the NorthBridge which is commonly used with it. This is the correct behavior, and was suggested by someone during the thread I reference, however this aspect of the fix was

No, this is NOT correct behaviour. Please read the pages at:
http://home.tiscalinet.de/au-ja/review-kt133a-1-en.html (and especially click on "Bugfix for everybody"); this URL is in the code. You will note that it is explicitly stated that this fix is NOT meant for any other Northbridge than VIA. So, in short, if there is no BIOS update available for your board, you're going to have to some more research. The PCI registers that are configured could have a totally different (and even dangerous) effect on your configuration.

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charl p. botha      | computer graphics and cad/cam 
http://cpbotha.net/ | http://www.cg.its.tudelft.nl/