Hello,

The following commit caused my X server to stop working.

commit 99fc8d424bc5d803fe92cad56c068fe64e73747a
Author: Jesse Barnes <[EMAIL PROTECTED]>
Date:   Wed Jan 30 13:33:18 2008 +0100

    x86, 32-bit: trim memory not covered by wb mtrrs

This patch fixes the improper handling of addresses > 4G by 
mtrr_trim_uncached_memory.
This, now brings up X on my system.

Signed-off-by: Balaji Rao <[EMAIL PROTECTED]>

diff --git a/arch/x86/kernel/cpu/mtrr/main.c b/arch/x86/kernel/cpu/mtrr/main.c
index 1e27b69..b0f1d48 100644
--- a/arch/x86/kernel/cpu/mtrr/main.c
+++ b/arch/x86/kernel/cpu/mtrr/main.c
@@ -659,7 +659,7 @@ static __init int amd_special_default_mtrr(void)
  */
 int __init mtrr_trim_uncached_memory(unsigned long end_pfn)
 {
-       unsigned long i, base, size, highest_addr = 0, def, dummy;
+       unsigned long i, base, size, highest_pfn = 0, def, dummy;
        mtrr_type type;
        u64 trim_start, trim_size;
 
@@ -682,30 +682,27 @@ int __init mtrr_trim_uncached_memory(unsigned long 
end_pfn)
                mtrr_if->get(i, &base, &size, &type);
                if (type != MTRR_TYPE_WRBACK)
                        continue;
-               base <<= PAGE_SHIFT;
-               size <<= PAGE_SHIFT;
-               if (highest_addr < base + size)
-                       highest_addr = base + size;
+               if (highest_pfn < base + size)
+                       highest_pfn = base + size;
        }
 
        /* kvm/qemu doesn't have mtrr set right, don't trim them all */
-       if (!highest_addr) {
+       if (!highest_pfn) {
                printk(KERN_WARNING "WARNING: strange, CPU MTRRs all blank?\n");
                WARN_ON(1);
                return 0;
        }
 
-       if ((highest_addr >> PAGE_SHIFT) < end_pfn) {
+       if (highest_pfn < end_pfn) {
                printk(KERN_WARNING "WARNING: BIOS bug: CPU MTRRs don't cover"
                        " all of memory, losing %LdMB of RAM.\n",
-                       (((u64)end_pfn << PAGE_SHIFT) - highest_addr) >> 20);
+                       ((u64)(end_pfn - highest_pfn) << PAGE_SHIFT) >> 20);
 
                WARN_ON(1);
 
                printk(KERN_INFO "update e820 for mtrr\n");
-               trim_start = highest_addr;
-               trim_size = end_pfn;
-               trim_size <<= PAGE_SHIFT;
+               trim_start = highest_pfn << PAGE_SHIFT;
+               trim_size = end_pfn << PAGE_SHIFT;
                trim_size -= trim_start;
                add_memory_region(trim_start, trim_size, E820_RESERVED);
                update_e820();
--
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