Bob Montgomery wrote: > Here's the README for the patch: > > This patch changes the initialization of the GART (in > pci-gart.c:init_k8_gatt) to set the DisGartCpu bit in the GART Aperture > Control Register. Setting the bit Disables requests from the CPUs from > accessing the GART. In other words, CPU memory accesses within the > range of addresses in the aperture will not cause the GART to perform an > address translation. The aperture area was already being unmapped at > the kernel level with clear_kernel_mapping() to prevent accesses from > the CPU, but that kernel level unmapping is not in effect in the kexec'd > kdump kernel. By disabling the CPU-side accesses within the GART, which > does persist through the kexec of the kdump kernel, the kdump kernel is > prevented from interacting with the GART during accesses to the dump > memory areas which include the address range of the GART aperture. > Although the patch can be applied to the kdump kernel, it is not > exercised there because the kdump kernel doesn't attempt to initialize > the GART. > > Bob Montgomery > working at HP > > I made the following changes and it seems like it is working. --- linux-2.6.27-rc8/include/asm-x86/gart.h.orig 2008-10-08 09:41:23.000000000 -0400 +++ linux-2.6.27-rc8/include/asm-x86/gart.h 2008-10-08 09:44:35.000000000 -0400 @@ -42,7 +42,8 @@ static inline void enable_gart_translati /* Enable GART translation for this hammer. */ pci_read_config_dword(dev, AMD64_GARTAPERTURECTL, &ctl); ctl |= GARTEN; - ctl &= ~(DISGARTCPU | DISGARTIO); + ctl |= DISGARTCPU; + ctl &= ~(DISGARTIO); pci_write_config_dword(dev, AMD64_GARTAPERTURECTL, ctl); } The system doesn't reset now while copying /proc/vmcore. Thanks! Chandru