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add missing files plus tweak docs/maintain/ 

Signed-off-by: Leah Rowe <info@minifree.org>
master
Leah Rowe 2024-05-01 06:24:05 +01:00
parent 71fc7a1981
commit b7a4d7b121
2 changed files with 62 additions and 1 deletions
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52
site/docs/hardware/dell_thermal.md Normal file
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---
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:
<https://codeberg.org/libreboot/lbmk/issues/202>
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:
<https://www.kernel.org/doc/html/v4.12/admin-guide/pm/intel_pstate.html>
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.

11
site/docs/maintain/index.md
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@ -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