"MTRR allocation failed. Graphics performance may suffer" message

"MTRR allocation failed. Graphics performance may suffer" message

[Dmitry Nezhevenko]

Hi,

I've just noticed this in my dmesg:

[    0.950076] i915 0000:00:02.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16
[    0.950148] i915 0000:00:02.0: setting latency timer to 64
[    0.983710] mtrr: type mismatch for d0000000,10000000 old: write-back new: write-combining
[    0.983795] [drm] MTRR allocation failed.  Graphics performance may suffer.
[    0.984128] i915 0000:00:02.0: irq 46 for MSI/MSI-X
[    0.984135] [drm] Supports vblank timestamp caching Rev 1 (10.10.2010).
[    0.984202] [drm] Driver supports precise vblank timestamp query.
[    1.174276] vgaarb: device changed decodes: PCI:0000:00:02.0,olddecodes=io+mem,decodes=io+mem:owns=io+mem

Is it something important? Log is from 2.6.39 kernel but It's definitely not
2.6.38 -> 2.6.39 regression.

Graphics is followed:
00:02.0 VGA compatible controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07)

Full 2.6.39 dmesg
http://dion.org.ua/uploads/2011/05/dmesg_2.6.39.txt

-- 
WBR, Dmitry

Re: "MTRR allocation failed. Graphics performance may suffer" message

[Christophe Chabanois]

Same thing here for my MSI H67MA-E45 motherboard.
Stuff about MTRR in kernel logs :

[    0.000000] DMI: MSI MS-7678/H67MA-E45 (MS-7678), BIOS V1.6 02/15/2011
[    0.000000] e820 update range: 0000000000000000 - 0000000000010000 (usable)
 ==> (reserved)
[    0.000000] e820 remove range: 00000000000a0000 - 0000000000100000 (usable)
[    0.000000] No AGP bridge found
[    0.000000] last_pfn = 0x23fe00 max_arch_pfn = 0x400000000
[    0.000000] MTRR default type: uncachable
[    0.000000] MTRR fixed ranges enabled:
[    0.000000]   00000-9FFFF write-back
[    0.000000]   A0000-BFFFF uncachable
[    0.000000]   C0000-CFFFF write-protect
[    0.000000]   D0000-E7FFF uncachable
[    0.000000]   E8000-FFFFF write-protect
[    0.000000] MTRR variable ranges enabled:
[    0.000000]   0 base 000000000 mask E00000000 write-back
[    0.000000]   1 base 200000000 mask FC0000000 write-back
[    0.000000]   2 base 0BB800000 mask FFF800000 uncachable
[    0.000000]   3 base 0BC000000 mask FFC000000 uncachable
[    0.000000]   4 base 0C0000000 mask FC0000000 uncachable
[    0.000000]   5 base 23FE00000 mask FFFE00000 uncachable
[    0.000000]   6 disabled
[    0.000000]   7 disabled
[    0.000000]   8 disabled
[    0.000000]   9 disabled
[    0.000000] x86 PAT enabled: cpu 0, old 0x7040600070406, new 0x7010600070106
[    0.000000] original variable MTRRs
[    0.000000] reg 0, base: 0GB, range: 8GB, type WB
[    0.000000] reg 1, base: 8GB, range: 1GB, type WB
[    0.000000] reg 2, base: 3000MB, range: 8MB, type UC
[    0.000000] reg 3, base: 3008MB, range: 64MB, type UC
[    0.000000] reg 4, base: 3GB, range: 1GB, type UC
[    0.000000] reg 5, base: 9214MB, range: 2MB, type UC
[    0.000000] total RAM covered: 8118M
....
[    0.000000] mtrr_cleanup: can not find optimal value
[    0.000000] please specify mtrr_gran_size/mtrr_chunk_size
....
[    1.481097] mtrr: type mismatch for c0000000,10000000 old: write-back
 new: write-combining
[    1.481238] [drm] MTRR allocation failed.  Graphics performance may suffer.

In kernel I have set
CONFIG_MTRR_SANITIZER (in Processor Type And Features)