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    Subject[PATCH 4.14 138/164] HID: input: fix battery level reporting on BT mice
    Date
    4.14-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    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 */

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