4.14-stable review patch. If anyone has any objections, please let me know.
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From: Dmitry Torokhov dmitry.torokhov@gmail.com
commit 2e210bbb7429cdcf1a1a3ad00c1bf98bd9bf2452 upstream.
The commit 581c4484769e ("HID: input: map digitizer battery usage") assumed that devices having input (qas opposed to feature) report for battery strength would report the data on their own, without the need to be polled by the kernel; unfortunately it is not so. Many wireless mice do not send unsolicited reports with battery strength data and have to be polled explicitly. As a complication, stylus devices on digitizers are not normally connected to the base and thus can not be polled - the base can only determine battery strength in the stylus when it is in proximity.
To solve this issue, we add a special flag that tells the kernel to avoid polling the device (and expect unsolicited reports) and set it when report field with physical usage of digitizer stylus (HID_DG_STYLUS). Unless this flag is set, and we have not seen the unsolicited reports, the kernel will attempt to poll the device when userspace attempts to read "capacity" and "state" attributes of power_supply object corresponding to the devices battery.
Fixes: 581c4484769e ("HID: input: map digitizer battery usage") Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=198095 Cc: stable@vger.kernel.org Reported-and-tested-by: Martin van Es martin@mrvanes.com Signed-off-by: Dmitry Torokhov dmitry.torokhov@gmail.com Signed-off-by: Jiri Kosina jkosina@suse.cz Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/hid/hid-input.c | 24 +++++++++++++++++------- include/linux/hid.h | 9 ++++++++- 2 files changed, 25 insertions(+), 8 deletions(-)
--- a/drivers/hid/hid-input.c +++ b/drivers/hid/hid-input.c @@ -387,7 +387,8 @@ static int hidinput_get_battery_property break;
case POWER_SUPPLY_PROP_CAPACITY: - if (dev->battery_report_type == HID_FEATURE_REPORT) { + if (dev->battery_status != HID_BATTERY_REPORTED && + !dev->battery_avoid_query) { value = hidinput_query_battery_capacity(dev); if (value < 0) return value; @@ -403,17 +404,17 @@ static int hidinput_get_battery_property break;
case POWER_SUPPLY_PROP_STATUS: - if (!dev->battery_reported && - dev->battery_report_type == HID_FEATURE_REPORT) { + if (dev->battery_status != HID_BATTERY_REPORTED && + !dev->battery_avoid_query) { value = hidinput_query_battery_capacity(dev); if (value < 0) return value;
dev->battery_capacity = value; - dev->battery_reported = true; + dev->battery_status = HID_BATTERY_QUERIED; }
- if (!dev->battery_reported) + if (dev->battery_status == HID_BATTERY_UNKNOWN) val->intval = POWER_SUPPLY_STATUS_UNKNOWN; else if (dev->battery_capacity == 100) val->intval = POWER_SUPPLY_STATUS_FULL; @@ -486,6 +487,14 @@ static int hidinput_setup_battery(struct dev->battery_report_type = report_type; dev->battery_report_id = field->report->id;
+ /* + * Stylus is normally not connected to the device and thus we + * can't query the device and get meaningful battery strength. + * We have to wait for the device to report it on its own. + */ + dev->battery_avoid_query = report_type == HID_INPUT_REPORT && + field->physical == HID_DG_STYLUS; + dev->battery = power_supply_register(&dev->dev, psy_desc, &psy_cfg); if (IS_ERR(dev->battery)) { error = PTR_ERR(dev->battery); @@ -530,9 +539,10 @@ static void hidinput_update_battery(stru
capacity = hidinput_scale_battery_capacity(dev, value);
- if (!dev->battery_reported || capacity != dev->battery_capacity) { + if (dev->battery_status != HID_BATTERY_REPORTED || + capacity != dev->battery_capacity) { dev->battery_capacity = capacity; - dev->battery_reported = true; + dev->battery_status = HID_BATTERY_REPORTED; power_supply_changed(dev->battery); } } --- a/include/linux/hid.h +++ b/include/linux/hid.h @@ -512,6 +512,12 @@ enum hid_type { HID_TYPE_USBNONE };
+enum hid_battery_status { + HID_BATTERY_UNKNOWN = 0, + HID_BATTERY_QUERIED, /* Kernel explicitly queried battery strength */ + HID_BATTERY_REPORTED, /* Device sent unsolicited battery strength report */ +}; + struct hid_driver; struct hid_ll_driver;
@@ -554,7 +560,8 @@ struct hid_device { /* device repo __s32 battery_max; __s32 battery_report_type; __s32 battery_report_id; - bool battery_reported; + enum hid_battery_status battery_status; + bool battery_avoid_query; #endif
unsigned int status; /* see STAT flags above */