mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-05-05 14:40:12 -04:00
e853658de5
On many Qualcomm platforms the PMIC RTC control and time registers are read-only so that the RTC time can not be updated. Instead an offset needs be stored in some machine-specific non-volatile memory, which the driver can take into account. On machines like the Lenovo ThinkPad X13s the PMIC RTC drifts about one second every 3.5 hours, something which leads to repeated updates of the offset when NTP synchronisation is enabled. Reduce wear of the underlying flash storage (used for UEFI variables) by deferring writes until shutdown in case they appear to be due to clock drift. As an example, deferring writes when the new offset differs up to 30 s from the previous one reduces the number of writes on the X13s during a ten day session with the machine not suspending for more than four days in a row from up to 68 writes (every 3.5 h) to at most two (boot and shutdown). Tested-by: Jens Glathe <jens.glathe@oldschoolsolutions.biz> Tested-by: Steev Klimaszewski <steev@kali.org> Tested-by: Joel Stanley <joel@jms.id.au> Tested-by: Sebastian Reichel <sre@kernel.org> # Lenovo T14s Gen6 Signed-off-by: Johan Hovold <johan+linaro@kernel.org> Link: https://lore.kernel.org/r/20250219134118.31017-4-johan+linaro@kernel.org Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.