Hi,
I just booted Linux with kernel 4.1.3 on my NUC5CPYH with BIOS 031 and I get the following warning in the system logs:
[ 0.000000] WARNING: BIOS bug: CPU MTRRs don't cover all of memory, losing 768MB of RAM.
Is there an issue with the BIOS? I've got 4GB RAM in the NUC.
Thanks!
[ 0.000000] e820: update [mem 0x4aa00000-0xffffffff] usable ==> reserved
[ 0.000000] e820: update [mem 0x180000000-0x1afffffff] usable ==> reserved
[ 0.000000] WARNING: BIOS bug: CPU MTRRs don't cover all of memory, losing 768MB of RAM.
[ 0.000000] ------------[ cut here ]------------
[ 0.000000] WARNING: CPU: 0 PID: 0 at arch/x86/kernel/cpu/mtrr/cleanup.c:971 mtrr_trim_uncached_memory+0x2be/0x2e7()
[ 0.000000] Modules linked in:
[ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.1.3 #1
[ 0.000000] Hardware name: /NUC5CPYB, BIOS PYBSWCEL.86A.0031.2015.0601.1712 06/01/2015
[ 0.000000] 0000000000000000 0000000000000009 ffffffff816bd5c8 0000000000000000
[ 0.000000] ffffffff8103577a 0000000000000008 ffffffff820e09ec 0000000080000000
[ 0.000000] 0000000000000300 00000000001b0000 ffffffff82162e50 0000000000000001
[ 0.000000] Call Trace:
[ 0.000000] [<ffffffff816bd5c8>] ? dump_stack+0x40/0x50
[ 0.000000] [<ffffffff8103577a>] ? warn_slowpath_common+0x93/0xab
[ 0.000000] [<ffffffff820e09ec>] ? mtrr_trim_uncached_memory+0x2be/0x2e7
[ 0.000000] [<ffffffff820e09ec>] ? mtrr_trim_uncached_memory+0x2be/0x2e7
[ 0.000000] [<ffffffff820d9a97>] ? setup_arch+0x591/0xa60
[ 0.000000] [<ffffffff820d6a1f>] ? start_kernel+0x8b/0x3db
[ 0.000000] ---[ end trace 8fa0319deda8a52b ]---
[ 0.000000] update e820 for mtrr
[ 0.000000] e820: modified physical RAM map:
[ 0.000000] modified: [mem 0x0000000000000000-0x0000000000000fff] reserved
[ 0.000000] modified: [mem 0x0000000000001000-0x000000000003efff] usable
[ 0.000000] modified: [mem 0x000000000003f000-0x000000000003ffff] ACPI NVS
[ 0.000000] modified: [mem 0x0000000000040000-0x000000000009ffff] usable
[ 0.000000] modified: [mem 0x0000000000100000-0x000000001fffffff] usable
[ 0.000000] modified: [mem 0x0000000020000000-0x00000000201fffff] reserved
[ 0.000000] modified: [mem 0x0000000020200000-0x00000000425de017] usable
[ 0.000000] modified: [mem 0x00000000425de018-0x00000000425eb857] usable
[ 0.000000] modified: [mem 0x00000000425eb858-0x00000000425ec017] usable
[ 0.000000] modified: [mem 0x00000000425ec018-0x00000000425fc057] usable
[ 0.000000] modified: [mem 0x00000000425fc058-0x00000000470b6fff] usable
[ 0.000000] modified: [mem 0x00000000470b7000-0x0000000047136fff] reserved
[ 0.000000] modified: [mem 0x0000000047137000-0x0000000047147fff] ACPI data
[ 0.000000] modified: [mem 0x0000000047148000-0x000000004763bfff] ACPI NVS
[ 0.000000] modified: [mem 0x000000004763c000-0x0000000047948fff] reserved
[ 0.000000] modified: [mem 0x0000000047949000-0x0000000047b18fff] usable
[ 0.000000] modified: [mem 0x0000000047b19000-0x0000000047fc4fff] reserved
[ 0.000000] modified: [mem 0x0000000047fc5000-0x0000000047ffffff] usable
[ 0.000000] modified: [mem 0x00000000e00f8000-0x00000000e00f8fff] reserved
[ 0.000000] modified: [mem 0x00000000fed01000-0x00000000fed01fff] reserved
[ 0.000000] modified: [mem 0x00000000fed08000-0x00000000fed08fff] reserved
[ 0.000000] modified: [mem 0x00000000ff980000-0x00000000ffffffff] reserved
[ 0.000000] modified: [mem 0x0000000100000000-0x000000017fffffff] usable
[ 0.000000] modified: [mem 0x0000000180000000-0x00000001afffffff] reserved
[ 0.000000] e820: last_pfn = 0x180000 max_arch_pfn = 0x400000000
[ 0.000000] e820: last_pfn = 0x48000 max_arch_pfn = 0x400000000
[ 0.000000] found SMP MP-table at [mem 0x000fd7e0-0x000fd7ef] mapped at [ffff8800000fd7e0]
[ 0.000000] Scanning 1 areas for low memory corruption
[ 0.000000] Base memory trampoline at [ffff880000098000] 98000 size 24576
[ 0.000000] init_memory_mapping: [mem 0x00000000-0x000fffff]