2.6.28-stable review patch. If anyone has any objections, please let us know. ------------------ From: Suresh Siddha commit 5cca0cf15a94417f49625ce52e23589eed0a1675 upstream Thierry Vignaud reported: > http://bugzilla.kernel.org/show_bug.cgi?id=12372 > > On P4 with an SiS motherboard (video card is a SiS 651) > X server fails to start with error: > xf86MapVidMem: Could not mmap framebuffer (0x00000000,0x2000) (Invalid > argument) Here X is trying to map first 8KB of memory using /dev/mem. Existing code treats first 0-4KB of memory as non-RAM and 4KB-8KB as RAM. Recent code changes don't allow to map memory with different attributes at the same time. Fix this by treating the first 1MB legacy region as special and always track the attribute requests with in this region using linear linked list (and don't bother if the range is RAM or non-RAM or mixed) Reported-and-tested-by: Thierry Vignaud Signed-off-by: Suresh Siddha Signed-off-by: Venkatesh Pallipadi Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/mm/pat.c | 37 +++++++++++++++++++++++++++---------- 1 file changed, 27 insertions(+), 10 deletions(-) --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -333,11 +333,20 @@ int reserve_memtype(u64 start, u64 end, req_type & _PAGE_CACHE_MASK); } - is_range_ram = pagerange_is_ram(start, end); - if (is_range_ram == 1) - return reserve_ram_pages_type(start, end, req_type, new_type); - else if (is_range_ram < 0) - return -EINVAL; + /* + * For legacy reasons, some parts of the physical address range in the + * legacy 1MB region is treated as non-RAM (even when listed as RAM in + * the e820 tables). So we will track the memory attributes of this + * legacy 1MB region using the linear memtype_list always. + */ + if (end >= ISA_END_ADDRESS) { + is_range_ram = pagerange_is_ram(start, end); + if (is_range_ram == 1) + return reserve_ram_pages_type(start, end, req_type, + new_type); + else if (is_range_ram < 0) + return -EINVAL; + } new = kmalloc(sizeof(struct memtype), GFP_KERNEL); if (!new) @@ -437,11 +446,19 @@ int free_memtype(u64 start, u64 end) if (is_ISA_range(start, end - 1)) return 0; - is_range_ram = pagerange_is_ram(start, end); - if (is_range_ram == 1) - return free_ram_pages_type(start, end); - else if (is_range_ram < 0) - return -EINVAL; + /* + * For legacy reasons, some parts of the physical address range in the + * legacy 1MB region is treated as non-RAM (even when listed as RAM in + * the e820 tables). So we will track the memory attributes of this + * legacy 1MB region using the linear memtype_list always. + */ + if (end >= ISA_END_ADDRESS) { + is_range_ram = pagerange_is_ram(start, end); + if (is_range_ram == 1) + return free_ram_pages_type(start, end); + else if (is_range_ram < 0) + return -EINVAL; + } spin_lock(&memtype_lock); list_for_each_entry(entry, &memtype_list, nd) { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/