linux-kernel - Re: [PATCH 4.19 146/191] HID: wacom: Avoid entering wacom_wac_pen

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Date:   Wed, 4 Nov 2020 08:52:21 +0100
From:   Pavel Machek <pavel@....cz>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        Jason Gerecke <jason.gerecke@...om.com>,
        Ping Cheng <ping.cheng@...om.com>,
        Jiri Kosina <jkosina@...e.cz>
Subject: Re: [PATCH 4.19 146/191] HID: wacom: Avoid entering
 wacom_wac_pen_report for pad / battery

Hi!

> To correct this, we restore a version of the `WACOM_PAD_FIELD` check
> in `wacom_wac_collection()` and return early. This effectively prevents
> pad / battery collections from being reported until the very end of the
> report as originally intended.

Okay... but code is either wrong or very confusing:

> +++ b/drivers/hid/wacom_wac.c
> @@ -2729,7 +2729,9 @@ static int wacom_wac_collection(struct h
>  	if (report->type != HID_INPUT_REPORT)
>  		return -1;
>  
> -	if (WACOM_PEN_FIELD(field) && wacom->wacom_wac.pen_input)
> +	if (WACOM_PAD_FIELD(field))
> +		return 0;
> +	else if (WACOM_PEN_FIELD(field) && wacom->wacom_wac.pen_input)
>  		wacom_wac_pen_report(hdev, report);

wacom_wac_pen_report() can never be called, because WACOM_PEN_FIELD()
can not be true here; if it was we'd return in the line above.

Best regards,
								Pavel
-- 
http://www.livejournal.com/~pavelmachek

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