The problem: % dmesg | grep -i micro Atom PSE erratum detected, BIOS microcode update recommended Atom PSE erratum detected, BIOS microcode update recommended microcode: CPU0 sig=0x106c2, pf=0x4, revision=0x208 microcode: CPU1 sig=0x106c2, pf=0x4, revision=0x208 microcode: Microcode Update Driver: v2.00 , Peter Oruba I found out that some recent kernel that I loaded at an unknown time, was able to point out that I had ‘old’ microcode for my processor on my Aspire1 ZG5.

About a month ago, I installed Gentoo on the new-to-me Acer Aspire1. Installation went like anything else, it is just a normal x86 host after all. I don’t have everything on it working, because I don’t care. If you are looking for additional resources on getting the extras working, you may want to look here or here. The exciting part, that I got working and am ready to announce publicly, is my new atom-x86 binpkg repo.

The problem: $ dmesg |grep mtrr mtrr: no more MTRRs available I found on my ‘new-to-me’ AA1 that MTRR handling in the BIOS was messed up. Thanks to this [bug report][1] I figured out that I should compile the kernel with MTRR sanitizer enabled. That is: $ zgrep -i MTRR /proc/config.gz CONFIG_MTRR=y CONFIG_MTRR_SANITIZER=y CONFIG_MTRR_SANITIZER_ENABLE_DEFAULT=1 CONFIG_MTRR_SANITIZER_SPARE_REG_NR_DEFAULT=1 And output of /proc/mtrr is as follows. Before and after. $ cat /proc/mtrr reg00: base=0x0fffe0000 ( 4095MB), size= 128KB, count=1: write-protect reg01: base=0x0fffc0000 ( 4095MB), size= 128KB, count=1: uncachable reg02: base=0x000000000 ( 0MB), size= 512MB, count=1: write-back reg03: base=0x020000000 ( 512MB), size= 512MB, count=1: write-back reg04: base=0x03f800000 ( 1016MB), size= 8MB, count=1: uncachable reg05: base=0x03f600000 ( 1014MB), size= 2MB, count=1: uncachable reg06: base=0x03f500000 ( 1013MB), size= 1MB, count=1: uncachable reg07: base=0x000000000 ( 0MB), size= 128KB, count=1: uncachable after kernel modification: reg00: base=0x000000000 ( 0MB), size= 1024MB, count=1: write-back reg01: base=0x03f500000 ( 1013MB), size= 1MB, count=1: uncachable reg02: base=0x03f600000 ( 1014MB), size= 2MB, count=1: uncachable reg03: base=0x03f800000 ( 1016MB), size= 8MB, count=1: uncachable reg04: base=0x040000000 ( 1024MB), size= 256MB, count=1: write-combining This is needed for decent video playback with the on-board Intel 945 video.