From: Hans de Goede <hdegoede@redhat.com>
Date: Mon, 16 Aug 2021 13:30:07 +0200
Subject: ACPI: platform-profile: call sysfs_notify() from
platform_profile_store()
Patch-mainline: v5.15-rc1
Git-commit: b25d5a1cd19896bb87b399d6e24896cf6f854d44
References: jsc#SLE-19223
Drivers like thinkpad_acpi and ideapad_laptop call the
platform_profile_notify() helper when the profile is changed by hardware
(the embedded-controller/EC) in response to an EC handled hotkey.
This allows userspace to monitor for such changes by polling for POLLPRI
on the platform_profile sysfs file. But the profile can also be changed
underneath a userspace program monitoring it by anonther userspace program
storing a new value.
Add a sysfs_notify() call to platform_profile_store(), so that userspace
programs monitoring for changes also get notified in this case.
Also update the documentation to document that POLLPRI polling can be
used to watch for changes.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Lee, Chun-Yi <jlee@suse.com>
---
Documentation/ABI/testing/sysfs-platform_profile | 7 +++++++
drivers/acpi/platform_profile.c | 3 +++
2 files changed, 10 insertions(+)
--- a/Documentation/ABI/testing/sysfs-platform_profile
+++ b/Documentation/ABI/testing/sysfs-platform_profile
@@ -26,3 +26,10 @@ Contact: Hans de Goede <hdegoede@redhat.
Description: Reading this file gives the current selected profile for this
device. Writing this file with one of the strings from
platform_profile_choices changes the profile to the new value.
+
+ This file can be monitored for changes by polling for POLLPRI,
+ POLLPRI will be signalled on any changes, independent of those
+ changes coming from a userspace write; or coming from another
+ source such as e.g. a hotkey triggered profile change handled
+ either directly by the embedded-controller or fully handled
+ inside the kernel.
--- a/drivers/acpi/platform_profile.c
+++ b/drivers/acpi/platform_profile.c
@@ -106,6 +106,9 @@ static ssize_t platform_profile_store(st
}
err = cur_profile->profile_set(cur_profile, i);
+ if (!err)
+ sysfs_notify(acpi_kobj, NULL, "platform_profile");
+
mutex_unlock(&profile_lock);
if (err)
return err;