Add support for hot-removal of SSAM HID client devices.
Once a device has been hot-removed, further communication with it should
be avoided as it may fail and time out. While the device will be removed
as soon as we detect hot-removal, communication may still occur during
teardown, especially when unregistering notifiers.
While hot-removal is a surprise event that can happen at any time, try
to avoid communication as much as possible once it has been detected to
prevent timeouts that can slow down device removal and cause issues,
e.g. when quickly re-attaching the device.
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20220527023447.2460025-8-luzmaximilian@gmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
There is a lot of duplication of code in the HID low level drivers.
Better have everything in one place so we can eventually extend it
in a generic way.
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20211202095334.14399-4-benjamin.tissoires@redhat.com
Until now we have only ever seen HID devices with target ID 2. The new
Surface Laptop Studio however uses HID devices with target ID 1. Allow
matching this driver to those as well.
Cc: stable@vger.kernel.org # 5.14+
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20211021130904.862610-4-luzmaximilian@gmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Until now, we have only ever seen the REG-category registry being used
on devices addressed with target ID 2. In fact, we have only ever seen
Surface Aggregator Module (SAM) HID devices with target ID 2. For those
devices, the registry also has to be addressed with target ID 2.
Some devices, like the new Surface Laptop Studio, however, address their
HID devices on target ID 1. As a result of this, any target ID 2
commands time out. This includes event management commands addressed to
the target ID 2 REG-category registry. For these devices, the registry
has to be addressed via target ID 1 instead.
We therefore assume that the target ID of the registry to be used
depends on the target ID of the respective device. Implement this
accordingly.
Note that we currently allow the surface HID driver to only load against
devices with target ID 2, so these timeouts are not happening (yet).
This is just a preparation step before we allow the driver to load
against all target IDs.
Cc: stable@vger.kernel.org # 5.14+
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20211021130904.862610-3-luzmaximilian@gmail.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Getting a report (e.g. feature report) from a device requires us to send
a request indicating which report we want to retrieve and then waiting
for the corresponding response containing that report. We already
provide the response structure to the request call, but the request
isn't marked as a request that expects a response. Thus the request
returns before we receive the response and the response buffer indicates
a zero length response due to that.
This essentially means that the get-report calls are broken and will
always indicate that a report of length zero has been read.
Fix this by appropriately marking the request.
Fixes: b05ff1002a ("HID: Add support for Surface Aggregator Module HID transport")
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
We want to convert from 16 bit (unsigned) little endian values contained
in a packed struct to CPU native endian values here, not the other way
around. So replace cpu_to_le16() with get_unaligned_le16(), using the
latter instead of le16_to_cpu() to acknowledge that we are reading from
a packed struct.
Reported-by: kernel test robot <lkp@intel.com>
Fixes: b05ff1002a ("HID: Add support for Surface Aggregator Module HID transport")
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Add support for the legacy keyboard (KBD/TC=0x08) HID transport layer of
the Surface System Aggregator Module (SSAM) to the Surface HID driver.
On Surface Laptops 1 and 2, this interface is used to connect the
integrated keyboard.
Note that this subsystem interface essentially provides a limited HID
transport layer. In contrast to the generic HID interface (TC=0x15) used
on newer Surface models, this interface only allows (as far as we know)
for a single device to be connected and is otherwise severely limited in
terms of support for feature- and output-reports. Specifically, only
caps-lock-LED output-reports and a single read-only feature-report are
supported.
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Add a HID transport driver to support integrated HID devices on newer
Microsoft Surface models (specifically 7th-generation, i.e. Surface
Laptop 3, Surface Book 3, and later).
On those models, the internal keyboard and touchpad (as well as some
other HID devices with currently unknown function) are connected via the
generic HID subsystem (TC=0x15) of the Surface System Aggregator Module
(SSAM). This subsystem provides a generic HID transport layer, support
for which is implemented by this driver.
Co-developed-by: Blaž Hrastnik <blaz@mxxn.io>
Signed-off-by: Blaž Hrastnik <blaz@mxxn.io>
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
