diff options
| author | Andi Kleen <ak@suse.de> | 2007-06-20 12:23:32 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-06-20 14:27:25 -0700 |
| commit | 388c19e176436707eb30a81c7e4129e08769f92b (patch) | |
| tree | 168017ad573b12c35a39f52f3513c779de3fb8c8 /arch | |
| parent | 0b622330213ce0f0ee23199e433ed73284209b46 (diff) | |
x86: Disable DAC on VIA bridges
Several reports that VIA bridges don't support DAC and corrupt
data. I don't know if it's fixed, but let's just blacklist
them all for now.
It can be overwritten with iommu=usedac
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/i386/kernel/pci-dma.c | 27 | ||||
| -rw-r--r-- | arch/x86_64/kernel/pci-dma.c | 12 |
2 files changed, 39 insertions, 0 deletions
diff --git a/arch/i386/kernel/pci-dma.c b/arch/i386/kernel/pci-dma.c index 30b754f7cbe..048f09b6255 100644 --- a/arch/i386/kernel/pci-dma.c +++ b/arch/i386/kernel/pci-dma.c @@ -12,6 +12,7 @@ #include <linux/string.h> #include <linux/pci.h> #include <linux/module.h> +#include <linux/pci.h> #include <asm/io.h> struct dma_coherent_mem { @@ -148,3 +149,29 @@ void *dma_mark_declared_memory_occupied(struct device *dev, return mem->virt_base + (pos << PAGE_SHIFT); } EXPORT_SYMBOL(dma_mark_declared_memory_occupied); + +#ifdef CONFIG_PCI +/* Many VIA bridges seem to corrupt data for DAC. Disable it here */ + +int forbid_dac; +EXPORT_SYMBOL(forbid_dac); + +static __devinit void via_no_dac(struct pci_dev *dev) +{ + if ((dev->class >> 8) == PCI_CLASS_BRIDGE_PCI && forbid_dac == 0) { + printk(KERN_INFO "PCI: VIA PCI bridge detected. Disabling DAC.\n"); + forbid_dac = 1; + } +} +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID, via_no_dac); + +static int check_iommu(char *s) +{ + if (!strcmp(s, "usedac")) { + forbid_dac = -1; + return 1; + } + return 0; +} +__setup("iommu=", check_iommu); +#endif diff --git a/arch/x86_64/kernel/pci-dma.c b/arch/x86_64/kernel/pci-dma.c index 651ccfb0669..9f80aad3fe2 100644 --- a/arch/x86_64/kernel/pci-dma.c +++ b/arch/x86_64/kernel/pci-dma.c @@ -322,5 +322,17 @@ static int __init pci_iommu_init(void) return 0; } +#ifdef CONFIG_PCI +/* Many VIA bridges seem to corrupt data for DAC. Disable it here */ + +static __devinit void via_no_dac(struct pci_dev *dev) +{ + if ((dev->class >> 8) == PCI_CLASS_BRIDGE_PCI && forbid_dac == 0) { + printk(KERN_INFO "PCI: VIA PCI bridge detected. Disabling DAC.\n"); + forbid_dac = 1; + } +} +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID, via_no_dac); +#endif /* Must execute after PCI subsystem */ fs_initcall(pci_iommu_init); |