linux-kernel - Re: [PATCH 1/2] HID: apple: avoid setting up battery timer for devices without battery

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Message-ID: <aGJaBJLwA7vbq32k@fedora>
Date: Mon, 30 Jun 2025 11:33:56 +0200
From: José Expósito <jose.exposito89@...il.com>
To: Aditya Garg <gargaditya08@...e.com>
Cc: Jiri Kosina <jikos@...nel.org>, Benjamin Tissoires <bentiss@...nel.org>,
	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] HID: apple: avoid setting up battery timer for
 devices without battery

On Wed, Jun 25, 2025 at 07:46:03PM +0530, Aditya Garg wrote:
> Currently, the battery timer is set up for all devices using hid-apple,
> irrespective of whether they actually have a battery or not.
> 
> APPLE_RDESC_BATTERY is a quirk that indicates the device has a battery
> and needs the battery timer. This patch checks for this quirk before
> setting up the timer, ensuring that only devices with a battery will
> have the timer set up.
> 
> Fixes: 6e143293e17a ("HID: apple: Report Magic Keyboard battery over USB")
> Cc: stable@...r.kernel.org
> Signed-off-by: Aditya Garg <gargaditya08@...e.com>
> ---
>  drivers/hid/hid-apple.c | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/hid/hid-apple.c b/drivers/hid/hid-apple.c
> index b8b99eb01..b9f45c089 100644
> --- a/drivers/hid/hid-apple.c
> +++ b/drivers/hid/hid-apple.c
> @@ -959,10 +959,12 @@ static int apple_probe(struct hid_device *hdev,
>  		return ret;
>  	}
>  
> -	timer_setup(&asc->battery_timer, apple_battery_timer_tick, 0);
> -	mod_timer(&asc->battery_timer,
> -		  jiffies + msecs_to_jiffies(APPLE_BATTERY_TIMEOUT_MS));
> -	apple_fetch_battery(hdev);
> +	if (quirks & APPLE_RDESC_BATTERY) {
> +		timer_setup(&asc->battery_timer, apple_battery_timer_tick, 0);
> +		mod_timer(&asc->battery_timer,
> +			  jiffies + msecs_to_jiffies(APPLE_BATTERY_TIMEOUT_MS));
> +		apple_fetch_battery(hdev);
> +	}
>

The same here, the `out_err:` error case uses the timer and it can
be uninitialized.

Jose

>  	if (quirks & APPLE_BACKLIGHT_CTL)
>  		apple_backlight_init(hdev);
> @@ -985,7 +987,8 @@ static void apple_remove(struct hid_device *hdev)
>  {
>  	struct apple_sc *asc = hid_get_drvdata(hdev);
>  
> -	timer_delete_sync(&asc->battery_timer);
> +	if (asc->quirks & APPLE_RDESC_BATTERY)
> +		timer_delete_sync(&asc->battery_timer);
>  
>  	hid_hw_stop(hdev);
>  }
> -- 
> 2.43.0
>