diff --git a/site/docs/hardware/dell_thermal.md b/site/docs/hardware/dell_thermal.md new file mode 100644 index 0000000..a28552d --- /dev/null +++ b/site/docs/hardware/dell_thermal.md @@ -0,0 +1,52 @@ +--- +title: Dell Latitude thermal throttling +x-toc-enable: true +... + +On some Dell Latitude laptops, you may encounter random shutdowns on +heavy load. We believe this is because the SMSC EC is overly conservative +by default; it is in charge of handling thermals and fan control on this +machine. Our theory is that coreboot needs to write certain EC commands +to allow higher temperatures; please read: + + + +Basically, what you need to do is: + +* Use high quality thermal paste (don't use the same dried up paste that the + laptop came with, if you bought it on ebay for example). Arctic MX-6 is good. +* Check that the fan works reliably + +Also: the `intel_pstate` driver can be used to artifically cap CPU speed. See: + + + +When you use this machine, it is recommended that you cap the CPU speed once +you've booted into Linux. Set it to something like 50% at first. Then run a +stress test, for example: + + stress -c x + +Where `x` is the number of CPU cores, e.g. 2. Monitor the temperatures using +something like `xsensors`, making sure the CPU doesn't exceed 80c temperature. + +You can also monitor CPU speeds in Linux like so: + + watch -n .2 grep MHz /proc/cpuinfo + +This will let you know what speed you're at. You can use this to determine +whether the `intel_pstate` driver is working. How to cap speed to 50 percent, as +in the above example: + + echo 50 > /sys/devices/system/cpu/cpufreq/intel_pstate/max_perf_pct + +Gradually increase the CPU speed (up to 100 on `max_perf_pct`), waiting a few +minutes each time. You should ensure that your machine does not exceed 80C. + +Dell's thermal safety is far too protective by default, on some of these, and +we don't yet know how to properly configure it. Running a CPU below 80c in +temperature and never higher than that, is a good idea anyway, for the +long term life of your CPU. + +Regardless, thermal shutdown is extremely reliable on this machine, but Dell +makes it shut down *earlier*, before it can even start to CPU throttle. diff --git a/site/docs/maintain/index.md b/site/docs/maintain/index.md index 0e9491b..b1e660d 100644 --- a/site/docs/maintain/index.md +++ b/site/docs/maintain/index.md @@ -579,7 +579,9 @@ as: * `grub_scan_disk="ata"` * `uboot_config=default` (specify which U-Boot tree to use) * `release="n"` (example entry) -* `status=stable` +* `status=stable` (example entry) +* `xtree="default"` (example entry) +* `tree_depend="default"` (example entry) The `tree` value refers to `config/coreboot/TREE`; in other words, a given target could specify a name other than its own as the tree; it would then @@ -644,6 +646,13 @@ Recommended strings for `status` could be: `stable`, `unstable`, `broken` or `untested`. Alternatively, you might state `wip`. You can set whatever string you want here. +The `xtree` option specifies that a given tree with use a specific coreboot +tree for compiling crossgcc. This can be used to skip building gcc if OK on +a given board; two trees may use the same crossgcc as each other. + +The `tree_depend` option means that a given tree needs another tree, defined +by this variable, to also be present. + ### config/coreboot/BOARDNAME/warn.txt Additionally: the `warn.txt` file can be included alongside target.cfg, to