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@xxxxxxxxxx> --- Documentation/ABI/testing/sysfs-platform_profile | 7 +++++++ drivers/acpi/platform_profile.c | 3 +++ 2 files changed, 10 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-platform_profile b/Documentation/ABI/testing/sysfs-platform_profile index dae9c8941905..baf1d125f9f8 100644 --- a/Documentation/ABI/testing/sysfs-platform_profile +++ b/Documentation/ABI/testing/sysfs-platform_profile @@ -26,3 +26,10 @@ Contact: Hans de Goede <hdegoede@xxxxxxxxxx> 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. diff --git a/drivers/acpi/platform_profile.c b/drivers/acpi/platform_profile.c index dd2fbf38e414..d418462ab791 100644 --- a/drivers/acpi/platform_profile.c +++ b/drivers/acpi/platform_profile.c @@ -106,6 +106,9 @@ static ssize_t platform_profile_store(struct device *dev, } 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; -- 2.31.1
