Messages in this thread | | | Date | Sat, 28 Oct 2006 15:54:43 -0400 | From | Dave Jones <> | Subject | p4-clockmod N60 errata workaround. |
| |
Ben, For the best part of a year since that N60 errata workaround went in, I've had floods of complaints from users of that driver about this driver becoming even more useless than it was before "I had 8 frequencies, now I have 2" being the common complaint. which was to be expected given that the intention of the errata workaround was to cripple frequencies <2GHz.
The point worth noting however, is that none of these users ever noticed any problems when we didn't have the workaround in place, so they were somewhat miffed when it stopped working.
The actual errata states..
"If a system de-asserts STPCLK# at a 12.5% duty cycle, the processor is running below 2 GHz, and the processor thermal control circuit (TCC) on-demand clock modulation is active, the processor may hang. This erratum does not occur under the automatic mode of the TCC."
I believe the reason we never saw any problems is that we _are_ using the TCC by default. See the code in arch/i386/kernel/cpu/mcheck/p4.c intel_init_thermal() and friends.
So my current feeling is that we're working around an errata that can never happen, and crippling functionality in the process for no good reason. I'm leaning towards just removing this workaround.
Dave
-- http://www.codemonkey.org.uk - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |