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authorMaximilian Luz <luzmaximilian@gmail.com>2022-05-27 05:34:37 +0300
committerHans de Goede <hdegoede@redhat.com>2022-06-13 18:25:07 +0300
commitdc0393c76f378f68961587fd4f32de29fb8f0c79 (patch)
tree76bc05f10cbf6d7480ad6bfc8c890f9a2f654bf8
parent0eb6584068642767baab17c2e4385a6b9c029caa (diff)
downloadlinux-dc0393c76f378f68961587fd4f32de29fb8f0c79.tar.xz
platform/surface: aggregator: Allow devices to be marked as hot-removed
Some SSAM devices, notably the keyboard cover (keyboard and touchpad) on the Surface Pro 8, can be hot-removed. When this occurs, communication with the device may fail and time out. This timeout can unnecessarily block and slow down device removal and even cause issues when the devices are detached and re-attached quickly. Thus, communication should generally be avoided once hot-removal is detected. While we already remove a device as soon as we detect its (hot-)removal, the corresponding device driver may still attempt to communicate with the device during teardown. This is especially critical as communication failure may also extend to disabling of events, which is typically done at that stage. Add a flag to allow marking devices as hot-removed. This can then be used during client driver teardown to check if any communication attempts should be avoided. Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com> Link: https://lore.kernel.org/r/20220527023447.2460025-3-luzmaximilian@gmail.com Reviewed-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
-rw-r--r--include/linux/surface_aggregator/device.h48
1 files changed, 45 insertions, 3 deletions
diff --git a/include/linux/surface_aggregator/device.h b/include/linux/surface_aggregator/device.h
index 62b38b4487eb..6df7c8d4e50e 100644
--- a/include/linux/surface_aggregator/device.h
+++ b/include/linux/surface_aggregator/device.h
@@ -148,17 +148,30 @@ struct ssam_device_uid {
#define SSAM_SDEV(cat, tid, iid, fun) \
SSAM_DEVICE(SSAM_DOMAIN_SERIALHUB, SSAM_SSH_TC_##cat, tid, iid, fun)
+/*
+ * enum ssam_device_flags - Flags for SSAM client devices.
+ * @SSAM_DEVICE_HOT_REMOVED_BIT:
+ * The device has been hot-removed. Further communication with it may time
+ * out and should be avoided.
+ */
+enum ssam_device_flags {
+ SSAM_DEVICE_HOT_REMOVED_BIT = 0,
+};
+
/**
* struct ssam_device - SSAM client device.
- * @dev: Driver model representation of the device.
- * @ctrl: SSAM controller managing this device.
- * @uid: UID identifying the device.
+ * @dev: Driver model representation of the device.
+ * @ctrl: SSAM controller managing this device.
+ * @uid: UID identifying the device.
+ * @flags: Device state flags, see &enum ssam_device_flags.
*/
struct ssam_device {
struct device dev;
struct ssam_controller *ctrl;
struct ssam_device_uid uid;
+
+ unsigned long flags;
};
/**
@@ -252,6 +265,35 @@ int ssam_device_add(struct ssam_device *sdev);
void ssam_device_remove(struct ssam_device *sdev);
/**
+ * ssam_device_mark_hot_removed() - Mark the given device as hot-removed.
+ * @sdev: The device to mark as hot-removed.
+ *
+ * Mark the device as having been hot-removed. This signals drivers using the
+ * device that communication with the device should be avoided and may lead to
+ * timeouts.
+ */
+static inline void ssam_device_mark_hot_removed(struct ssam_device *sdev)
+{
+ dev_dbg(&sdev->dev, "marking device as hot-removed\n");
+ set_bit(SSAM_DEVICE_HOT_REMOVED_BIT, &sdev->flags);
+}
+
+/**
+ * ssam_device_is_hot_removed() - Check if the given device has been
+ * hot-removed.
+ * @sdev: The device to check.
+ *
+ * Checks if the given device has been marked as hot-removed. See
+ * ssam_device_mark_hot_removed() for more details.
+ *
+ * Return: Returns ``true`` if the device has been marked as hot-removed.
+ */
+static inline bool ssam_device_is_hot_removed(struct ssam_device *sdev)
+{
+ return test_bit(SSAM_DEVICE_HOT_REMOVED_BIT, &sdev->flags);
+}
+
+/**
* ssam_device_get() - Increment reference count of SSAM client device.
* @sdev: The device to increment the reference count of.
*