Commit 55c49455 authored by David Boddie's avatar David Boddie
Browse files

Merge branch 'resolve-describe-reset-prevention' into 'master'

Add a page to cover power issues and workarounds

Closes #93

See merge request Librem5/developer.puri.sm!270
parents 9601ac58 6cab20b9
Pipeline #52287 passed with stages
in 1 minute and 45 seconds
......@@ -32,6 +32,11 @@ Issues
driver.
See `dvk-mx8m-bsb issue 3 <https://source.puri.sm/Librem5/dvk-mx8m-bsb/issues/3>`_
for details.
* When running older versions of the system software the board could reset when
under heavy load, either due to processor-intensive software or peripherals
that draw large currents.
See :ref:`imx8_devkit_troubleshooting_resets` for possible workarounds for
this behavior.
Status of Subsystems
--------------------
......
......@@ -19,3 +19,4 @@ may be needed to help with testing.
Troubleshooting/Install_Minimal_Linux
Troubleshooting/Installing_SOM
Troubleshooting/Reflashing_RS9116
Troubleshooting/Spurious_Resets
.. _imx8_devkit_troubleshooting_resets:
Spurious Resets
===============
The development board may spuriously reset when under heavy load when running
older versions of the system software. This can be due to processor-intensive software (see `this issue <linux-emcraft issue 22_>`_) or when power-intensive peripherals are active (see `this issue <linux-emcraft issue 27_>`_).
Updating the system image to the latest version can help to avoid these issues
-- see :ref:`imx8_devkit_flashing_emmc` for instructions on how to do this.
If your development board does not unexpectedly reset during use then there is no need to take action. However, if it becomes an issue then the following information may be useful.
Power Related Resets
--------------------
Power over USB 2 or USB 3 from a laptop or workstation is not enough to supply enough power during heavy load -- even the upper current limit that USB 3 hosts can supply is lower than what some components on the development board may require in certain situations.
Using the USB power adapter supplied with the development kit to directly power the board should avoid power-related resets. This has the disadvantage that this makes the USB connection unavailable for communication with a workstation.
A properly-charged battery should also be able to supply enough power in all situations and is useful for handling transient spikes in the current load. It is also useful when you need to use the USB connection for communication with a workstation.
Only batteries meeting the specification given in :ref:`imx8_devkit` should be used to avoid safety issues.
If you decide to use a battery, note that Linux 4.18 does not include support for battery charging for the development board, so a charger will also be needed for charging the battery separately.
Overheating Resets
------------------
The board can overheat when under heavy load, particularly when compiling complex pieces of software. Later kernels than the one initially installed on
the board tend to prevent this issue.
Some resets are caused by the system shutting down due to overheating. This can be verified by monitoring the ``/sys/class/thermal/thermal_zone0/temp`` file which contains temperatures measured in millidegrees Celsius. Consider using a cooling fan to ensure a steady flow of air over the CPU if the temperature regularly exceeds 80°C.
.. include:: /links.txt
......@@ -135,6 +135,8 @@
.. _`librem5-m2-breakout repository`: https://source.puri.sm/Librem5/librem5-m2-breakout
.. _`linux-emcraft repository`: https://source.puri.sm/Librem5/linux-emcraft/
.. _`linux-emcraft issue 2`: https://source.puri.sm/Librem5/linux-emcraft/issues/2
.. _`linux-emcraft issue 22`: https://source.puri.sm/Librem5/linux-emcraft/issues/22
.. _`linux-emcraft issue 27`: https://source.puri.sm/Librem5/linux-emcraft/issues/27
.. _`linux-next repository`: https://source.puri.sm/Librem5/linux-next/
.. _`Meson`: https://mesonbuild.com/
.. _`Meson Localisation guide`: https://mesonbuild.com/Localisation.html
......
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