W dniu 31.03.2022 o 21:21, Greg KH pisze:
On Thu, Mar 31, 2022 at 09:06:11PM +0200, Mateusz Jończyk wrote:
Before Linux 5.17, there was a problem with the CMOS RTC driver: cmos_read_alarm() and cmos_set_alarm() did not check for the UIP (Update in progress) bit, which could have caused it to sometimes fail silently and read bogus values or do not set the alarm correctly. Luckily, this issue was masked by cmos_read_time() invocations in core RTC code - see https://marc.info/?l=linux-rtc&m=164858416511425&w=4
[snip]
diff --git a/drivers/rtc/debugfs.c b/drivers/rtc/debugfs.c new file mode 100644 index 000000000000..5ceed5504033 --- /dev/null +++ b/drivers/rtc/debugfs.c @@ -0,0 +1,112 @@ +// SPDX-License-Identifier: GPL-2.0-or-later
+/*
- Debugfs interface for testing RTC alarms.
- */
+#include <linux/debugfs.h> +#include <linux/err.h> +#include <linux/rtc.h>
+static struct dentry *rtc_main_debugfs_dir;
+void rtc_debugfs_init(void) +{
- struct dentry *ret = debugfs_create_dir("rtc", NULL);
- // No error is critical here
What do you mean by this?
I meant that even if debugfs_create_dir() fails, this does not matter here and the caller of rtc_debugfs_init() may continue execution.
- if (!IS_ERR(ret))
rtc_main_debugfs_dir = ret;This should not be needed.
Just set the directory and away you go.
But why even save it? If you need it you can always look it up, right?
OK, I did not know about easy lookup of debugfs directories.
And when are you removing this directory you created?
Never, as the RTC subsystem cannot be compiled as a module. This is the main debugfs directory of RTC subsystem, directories for specific devices (rtc0, etc.) are created below it. Please correct me if I'm wrong, but I thought that empty debugfs directories do not hurt.
Thanks for reviewing,
Mateusz