* [PATCH] ACPI: platform-profile: call sysfs_notify() from platform_profile_store()
@ 2021-08-16 11:30 Hans de Goede
2021-08-16 16:33 ` Rafael J. Wysocki
0 siblings, 1 reply; 2+ messages in thread
From: Hans de Goede @ 2021-08-16 11:30 UTC (permalink / raw)
To: Rafael J . Wysocki
Cc: Hans de Goede, Mark Pearson, Len Brown, Andy Shevchenko,
Luke D . Jones, linux-acpi, platform-driver-x86
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>
---
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@redhat.com>
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
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] ACPI: platform-profile: call sysfs_notify() from platform_profile_store()
2021-08-16 11:30 [PATCH] ACPI: platform-profile: call sysfs_notify() from platform_profile_store() Hans de Goede
@ 2021-08-16 16:33 ` Rafael J. Wysocki
0 siblings, 0 replies; 2+ messages in thread
From: Rafael J. Wysocki @ 2021-08-16 16:33 UTC (permalink / raw)
To: Hans de Goede
Cc: Rafael J . Wysocki, Mark Pearson, Len Brown, Andy Shevchenko,
Luke D . Jones, ACPI Devel Maling List, Platform Driver
On Mon, Aug 16, 2021 at 1:30 PM Hans de Goede <hdegoede@redhat.com> wrote:
>
> 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>
> ---
> 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@redhat.com>
> 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;
> --
Applied as 5.15 material, thanks!
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2021-08-16 16:33 ` Rafael J. Wysocki
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