b411f9463a
[ Upstream commit fbb974ba693bbfb4e24a62181ef16d4e45febc37 ] When there is no IRQ configured for the RTC, the rtc-cmos code does not support alarms, all alarm rtc_ops fail with -EIO / -EINVAL. The rtc-core expects a rtc driver which does not support rtc alarms to not have alarm ops at all. Otherwise the wakealarm sysfs attr will read as empty rather then returning an error, making it impossible for userspace to find out beforehand if alarms are supported. A system without an IRQ for the RTC before this patch: [root@localhost ~]# cat /sys/class/rtc/rtc0/wakealarm [root@localhost ~]# After this patch: [root@localhost ~]# cat /sys/class/rtc/rtc0/wakealarm cat: /sys/class/rtc/rtc0/wakealarm: No such file or directory [root@localhost ~]# This fixes gnome-session + systemd trying to use suspend-then-hibernate, which causes systemd to abort the suspend when writing the RTC alarm fails. BugLink: https://github.com/systemd/systemd/issues/9988 Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
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 Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
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.