4 Replies Latest reply on Sep 18, 2015 7:09 PM by N.Scott.Pearson

    NUC5CPYH BIOS bug? Not all memory usable

    trsqr

      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]

        • 1. Re: NUC5CPYH BIOS bug? Not all memory usable
          trsqr

          That was from OpenELEC, so I booted into a more mainstream distribution. I can see the same warning line in Ubuntu 15.04. Here's the whole boot up log:

          Ubuntu Pastebin

           

          Also, I can only see a bit more than 3 gigabytes of memory being used! As if this was a 32-bit system... However, it is the 64-bit version of Ubuntu.

           

          braswell:~$ cat /proc/meminfo

          MemTotal:        3191968 kB

          MemFree:         2167212 kB

          MemAvailable:    2594392 kB


          I'll add still that the memory chip is the Kingston KVR16LS11/4 that is on Intel's list of compatible memory.

          • 2. Re: NUC5CPYH BIOS bug? Not all memory usable
            trsqr

            Any comment from Intel on this? Is there an "officially supported" Linux distribution that I could try out on the NUC5CPYH?

            • 3. Re: NUC5CPYH BIOS bug? Not all memory usable
              darwinb_intel

              Hello Trsqr,

               

              Officially only Microsoft operating systems are fully support by our NUCs but based on feedback from users Linux distros like Lubuntu, OpenELEC, and Ubuntu have been tested fine in this particular model.

               

              For more information about supported operating systems see:

              http://www.intel.com/support/motherboards/desktop/sb/CS-034034.htm

               

              In regards of the problem you reported we need to identify if this is memory addressing issue generated by the Memory Controller Hub (MCH) or eventually an operating system incompatibility.

               

              So far we have not received similar reports since these units were released. I am afraid that in order to investigate about this issue we need to install a supported Windows version (Windows 7, Windows 8.1, Windows 10) and comparing the memory use.

              • 4. Re: NUC5CPYH BIOS bug? Not all memory usable
                N.Scott.Pearson

                The BIOS reserves a chunk of the memory range for its own usage. A significant portion of this is assigned for use by the graphics subsystem; its size depended upon the BIOS video configuration.

                 

                ...Scott