List, here's a rant about a recent problem I had and the surprising solution.
I recently had to investigate weird unexpected issues on a workstation. Relevant hardware: Asus P8B-WS, Xeon E3-1260L (Sandy Bride, Intel HD-2000 graphics) Since we don't have kms and friends in STABLE yet, and I can live without accelerated video for now, I am using the vesa driver on this machine. Initially, this had two major drawbacks: 1) 1280x1024 resolution utterly sucks on a 1680x1050 screen. 2) Reproducable unhandled MCA events (and subsequent kernel panics) like the following whenever I switch from X to console: panic: machine check trap ... MCA: CPU 6 UNCOR UNCOR UNCOR PCC PCC PCC internal error 2internal error 2PCC internal error 2 The kernel dump _always_ showed something like: current process = 11 (idle: cpu3) trap number = 28 #1 0xffffffff805db167 at panic+0x187 #2 0xffffffff808c6820 at trap_fatal+0x290 #3 0xffffffff808c6d3a at trap+0x10a #4 0xffffffff808ae894 at calltrap+0x8 #5 0xffffffff801f6b9a at acpi_cpu_idle+0x20a #6 0xffffffff806003af at sched_idletd+0x11f #7 0xffffffff805afe6f at fork_exit+0x11f #8 0xffffffff808aedde at fork_trampoline+0xe mcelog did not help decoding the MCA output and the "internal error2" message made me suspect that this CPU was maybe just broken. However, due to my utter inabilty of producing the slightest other problem with this machine (constantly heavy CPU + IO load) or any problem using other operating systems I derived the wild speculation that there might be something with the Sandy Bridge silicon which this exact sequence of actions on FreeBSD reliably could trigger. Long story short: I got the latest Bios from Asus for this Board. The changelog of course said absolutely nothing about fixing any known problem. Upon boot I entered the Bios settings and noticed that it apparently contained a microcode update. The changelog for microcode from Intel is of course non-existing. And since this boot there has not been a single problem with this machine. Vesa now works in 1680x1050 and switching from X to console and back does not trigger MCA events anymore. I like to believe that for the first time a microcode update from Intel fixed my specific problem. Anyway, now the story is on the list and for Google to find, in case anyone else has this problem as well. Best regards Riggs -- - Now the world has gone to bed | Now I lay me down to sleep - -- Darkness won't engulf my head | Try to count electric sheep -- --- I can see by infra-red | Sweet dream wishes you can keep --- ---- How I hate the night | How I hate the night ---- _______________________________________________ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"
