add missing files plus tweak docs/maintain/

Signed-off-by: Leah Rowe <info@minifree.org>

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:
+
+<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.

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