Messages in this thread | | | Date | Tue, 1 Apr 2014 14:16:40 -0400 | From | Paul Gortmaker <> | Subject | Regression in intel_idle on Avaton/Rangely Mohon Peak board |
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Hi Len,
I've got an eval board with a 1.7GHz Avaton/C2000 that hangs at boot shortly after the idle driver registration -- typically 1/2 dozen dmesg lines later, around rtc init, or net stack init.
It may be that this early board/early bios makes it a non-issue for mainline, but I figured I'd better mention it anyway.
Problem starts with commit v3.12-rc4-32-gfab04b2208dd ("intel_idle: Support Intel Atom Processor C2000 Product Family").
Even though a bisect leads here, this commit shouldn't be considered in isolation however, since it depends on these earlier v3.12 commits:
commit v3.12-rc2-1-geba682a5aeb6 "intel_idle: shrink states tables"
commit v3.12-rc2-2-g9d046ccb9808 "intel_idle: mark states tables with __initdata tag"
..and then these v3.13 subsequent fixups;
commit v3.13-rc1-1-g22e580d07f65 "intel_idle: Fixed C6 state on Avoton/Rangeley processors"
commit v3.13-rc7-1-gba0dc81ed5d9 "Revert "intel_idle: mark states tables with __initdata tag""
commit v3.13-rc7-2-g88390996c95b "intel_idle: close avn_cstates array with correct marker"
However, even with all these present in v3.13-final, the board still does the same thing as the bisected fab 04 commit. Same for v3.14-final and today's linux-next -- i.e. the regression remains uninterrupted.
The interesting part is that a nearly identical board, but with different (newer/faster) CPU and newer BIOS doesn't have the hang.
Hardware details:
board: intel Mohon Peak CRB GA-95PEV ALPHA2 rev0.3 BIOS: EDVLCRB1.86B.0010.R00.1303272109 03/27/2013 CPU (dmidecode): Family: Pentium 4 ID: D0 06 04 00 FF FB EB 9F Signature: Type 0, Family 6, Model 77, Stepping 0 Version: Genuine Intel(R) CPU 4000 @ 1.70GHz
The same board that doesn't hang, for comparison, has:
BIOS: EDVLCRB1.86B.0017.R00.1305271414 05/27/2013 CPU: (dmidecode): Family: Pentium 4 ID: D0 06 04 00 FF FB EB 9F Signature: Type 0, Family 6, Model 77, Stepping 0 Version: Genuine Intel(R) CPU 4000 @ 2.40GHz
Since it appears only the clock multiplier has changed, I'm guessing we've hit a bug in the earlier BIOS. These boards don't have flash capable BIOS AFAICT -- looks like the little trap-door socket style that houses a removable chip?
I have the full dmidecode files, dmesg from 3.11-distro kernel, lspci, and /proc/cpuinfo from both boards, if that is needed.
Paul.
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