While events can already be enabled and disabled via the generic request
IOCTL, this bypasses the internal reference counting mechanism of the
controller. Due to that, disabling an event will turn it off regardless
of any other client having requested said event, which may break
functionality of that client.
To solve this, add IOCTLs wrapping the ssam_controller_event_enable()
and ssam_controller_event_disable() functions, which have been
previously introduced for this specific purpose.
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210604134755.535590-6-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Currently, debugging unknown events requires writing a custom driver.
This is somewhat difficult, slow to adapt, and not entirely
user-friendly for quickly trying to figure out things on devices of some
third-party user. We can do better. We already have a user-space
interface intended for debugging SAM EC requests, so let's add support
for receiving events to that.
This commit provides support for receiving events by reading from the
controller file. It additionally introduces two new IOCTLs to control
which event categories will be forwarded. Specifically, a user-space
client can specify which target categories it wants to receive events
from by registering the corresponding notifier(s) via the IOCTLs and
after that, read the received events by reading from the controller
device.
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210604134755.535590-5-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
The Microsoft Surface Book series devices consist of a so-called
clipboard part (containing the CPU, touchscreen, and primary battery)
and a base part (containing keyboard, secondary battery, and optional
discrete GPU). These parts can be separated, i.e. the clipboard can be
detached and used as tablet.
This detachment process is initiated by pressing a button. On the
Surface Book 2 and 3 (targeted with this commit), the Surface Aggregator
Module (i.e. the embedded controller on those devices) attempts to send
a notification to any listening client driver and waits for further
instructions (i.e. whether the detachment process should continue or be
aborted). If it does not receive a response in a certain time-frame, the
detachment process (by default) continues and the clipboard can be
physically separated. In other words, (by default and) without a driver,
the detachment process takes about 10 seconds to complete.
This commit introduces a driver for this detachment system (called DTX).
This driver allows a user-space daemon to control and influence the
detachment behavior. Specifically, it forwards any detachment requests
to user-space, allows user-space to make such requests itself, and
allows handling of those requests. Requests can be handled by either
aborting, continuing/allowing, or delaying (i.e. resetting the timeout
via a heartbeat commend). The user-space API is implemented via the
/dev/surface/dtx miscdevice.
In addition, user-space can change the default behavior on timeout from
allowing detachment to disallowing it, which is useful if the (optional)
discrete GPU is in use.
Furthermore, this driver allows user-space to receive notifications
about the state of the base, specifically when it is physically removed
(as opposed to detachment requested), in what manner it is connected
(i.e. in reverse-/tent-/studio- or laptop-mode), and what type of base
is connected. Based on this information, the driver also provides a
simple tablet-mode switch (aliasing all modes without keyboard access,
i.e. tablet-mode and studio-mode to its reported tablet-mode).
An implementation of such a user-space daemon, allowing configuration of
detachment behavior via scripts (e.g. safely unmounting USB devices
connected to the base before continuing) can be found at [1].
[1]: https://github.com/linux-surface/surface-dtx-daemon
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20210308184819.437438-2-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Add a misc-device providing user-space access to the Surface Aggregator
EC, mainly intended for debugging, testing, and reverse-engineering.
This interface gives user-space applications the ability to send
requests to the EC and receive the corresponding responses.
The device-file is managed by a pseudo platform-device and corresponding
driver to avoid dependence on the dedicated bus, allowing it to be
loaded in a minimal configuration.
A python library and scripts to access this device can be found at [1].
[1]: https://github.com/linux-surface/surface-aggregator-module/tree/master/scripts/ssam
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20201221183959.1186143-9-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
