On 03/11/2012 01:54 AM, Jason Vas Dias wrote: > Hi - since many kernel versions ago (I believe 2.6.38+), now running > 3.1.1 (built from 'stable' GIT tree), > CPU frequency throttling once the maximum fans have been enabled does > not work after I resume > my HP 6715b x86_64 2.2GHz TL64 dual-core laptop from disk . The trip > point temperatures are : > $ cat /sys/class/thermal/thermal_zone0/trip_point_*temp | tr '\n' ' ' > 105000 95000 75000 65000 50000 15900 > > When the 95-degree thermal_zone0 trip point is exceeded, the CPU is > meant to be throttled back from 2.2Ghz to 800Khz, until the > temperature > falls below the trip point when the normal frequency is restored (with > some hystereisis delay factor) . > > On boot-up from a 'pm-hibernate' suspend-to-disk on my laptop , > however, the 95-degree trip point is triggered, but no CPU frequency > throttling occurs, and no below-95-degree > trip-point is triggerred, so the CPU eventually reaches the 105 degree > trip-point and does an emergency power-off if it is heavily loaded. > Also, the system > in this state generates only one 95 degree trip-point event ; after > the temperature falls below 95-degrees for some time (over 10mins) , > and then I load > the machine again, so the temperature again exceeds 95-degrees, no > ACPI thermal event is raised . > > This occurs with ANY available "governor" - I use "ondemand" by > default, with a 'scaling_max_freq' set to 2.0Ghz (because when I run > the CPU at 2.2Ghz , and load the machine > (with for instance a large package 'make -j2' build) I get hardware > 'system hang' issues - I've tried every available means to get the > kernel to trace / log something or boot a crash > kernel when this occurs, with no luck, so have concluded this is a > hardware issue - it did not occur when the laptop was new (it is now > nearly 4 years old) - since the machine goes > into a state that is totally unresponsive to anything (mouse, > keyboard, networking, video, serial, parport, USB devices all hang), > only a PCI bus analyzer will help solve this). > But I've reproduced the no-throttling- > above-95-degrees-after-suspend-from-disk problem with EVERY governor: > performance, userspace, etc. I have the powernow-k8 CPU > frequency scaling module built-in to the kernel. > > I've resorted to hacking together an acpid driven thermal.sh shell > script that, on receipt of a 95 degree event, spawns a daemon process > that periodically monitors > the thermal_zone0 temperature and if the temp is above 95 and the freq > is above 800Khz, sets the frequency down a notch, and back to where it > was > when the temperature falls below 95 degrees. > > Is this a known kernel issue ? Should I raise a bug about this ? I can > post detailed logs showing the events occurring and CPU frequency > throttling when booted up from cold, > and no frequency scaling and only one 95-degree event when booted from > suspend to disk - I wanted to check if this was a known issue first (a > bugzilla search for > 'no ACPI thermal event after resume from disk' returned zarro boogs). > > Comments and advice would be much appreciated, > Just a wild guess, but does the patch posted below help? https://lkml.org/lkml/2012/2/28/288 (It applies on current Linux mainline.) Regards, Srivatsa S. Bhat IBM Linux Technology Center -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
