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platform/chrome: Resolve kb_wake_angle visibility race

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A race condition exists between the probe of cros-ec-sysfs and
cros-ec-sensorhub.

The `kb_wake_angle` attribute should only be visible if the sensor hub
detects two or more accelerometers.  If cros_ec_sysfs_probe() runs
before cros_ec_sensorhub_register() completes sensor enumeration, the
sysfs attributes are created while `has_kb_wake_angle` is still false,
hiding `kb_wake_angle` incorrectly.

Store the created attribute group pointer in `ec_dev->group`.  When
the sensor hub completes sensor enumeration, it checks for this group
and calls sysfs_update_group() to notify the sysfs core to re-evaluate
attribute visibility.  This ensures the `kb_wake_angle` attribute
visibility is correctly updated regardless of the driver probe order.

Co-developed-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Link: https://lore.kernel.org/r/20260407102615.1605317-1-tzungbi@kernel.org
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
This commit is contained in:
Tzung-Bi Shih 2026-04-07 10:26:15 +00:00
parent 5d6919055d
commit c40f5f9927
3 changed files with 10 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/platform/chrome/cros_ec_sensorhub.c
View File

@ -122,8 +122,12 @@ static int cros_ec_sensorhub_register(struct device *dev,
sensor_type[sensorhub->resp->info.type]++;
}
if (sensor_type[MOTIONSENSE_TYPE_ACCEL] >= 2)
if (sensor_type[MOTIONSENSE_TYPE_ACCEL] >= 2) {
ec->has_kb_wake_angle = true;
if (ec->group && sysfs_update_group(&ec->class_dev.kobj,
ec->group))
dev_warn(dev, "Unable to update sysfs");
}
if (cros_ec_check_features(ec,
EC_FEATURE_REFINED_TABLET_MODE_HYSTERESIS)) {

5
drivers/platform/chrome/cros_ec_sysfs.c
View File

@ -405,7 +405,8 @@ static int cros_ec_sysfs_probe(struct platform_device *pd)
struct device *dev = &pd->dev;
int ret;
ret = sysfs_create_group(&ec_dev->class_dev.kobj, &cros_ec_attr_group);
ec_dev->group = &cros_ec_attr_group;
ret = sysfs_create_group(&ec_dev->class_dev.kobj, ec_dev->group);
if (ret < 0)
dev_err(dev, "failed to create attributes. err=%d\n", ret);
@ -416,7 +417,7 @@ static void cros_ec_sysfs_remove(struct platform_device *pd)
{
struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
sysfs_remove_group(&ec_dev->class_dev.kobj, &cros_ec_attr_group);
sysfs_remove_group(&ec_dev->class_dev.kobj, ec_dev->group);
}
static const struct platform_device_id cros_ec_sysfs_id[] = {

2
include/linux/platform_data/cros_ec_proto.h
View File

@ -228,6 +228,7 @@ struct cros_ec_platform {
/**
* struct cros_ec_dev - ChromeOS EC device entry point.
* @class_dev: Device structure used in sysfs.
* @group: sysfs attributes groups for this EC.
* @ec_dev: cros_ec_device structure to talk to the physical device.
* @dev: Pointer to the platform device.
* @debug_info: cros_ec_debugfs structure for debugging information.
@ -237,6 +238,7 @@ struct cros_ec_platform {
*/
struct cros_ec_dev {
struct device class_dev;
const struct attribute_group *group;
struct cros_ec_device *ec_dev;
struct device *dev;
struct cros_ec_debugfs *debug_info;