linux-kernel - Re: [PATCH] input: cros_ec_keyb: fix button/switch capability reports

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Date:   Mon, 12 Nov 2018 11:24:20 -0800
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Brian Norris <briannorris@...omium.org>
Cc:     Enric Balletbo i Serra <enric.balletbo@...labora.co.uk>,
        linux-kernel@...r.kernel.org, linux-input@...r.kernel.org,
        Doug Anderson <dianders@...omium.org>
Subject: Re: [PATCH] input: cros_ec_keyb: fix button/switch capability reports

On Wed, Nov 07, 2018 at 02:38:13PM -0800, Brian Norris wrote:
> The cros_ec_keyb_bs array lists buttons and switches together, expecting
> that its users will match the appropriate type and bit fields. But
> cros_ec_keyb_register_bs() only checks the 'bit' field, which causes
> misreported input capabilities in some cases. For example, tablets
> (e.g., Scarlet -- a.k.a. Acer Chromebook Tab 10) were reporting a SW_LID
> capability, because EC_MKBP_POWER_BUTTON and EC_MKBP_LID_OPEN happen to
> share the same bit.
> 
> (This has comedic effect on a tablet, in which a power-management daemon
> then thinks this "lid" is closed, and so puts the system to sleep as
> soon as it boots!)
> 
> To fix this, check both the 'ev_type' and 'bit' fields before reporting
> the capability.
> 
> Tested with a lid (Kevin / Samsung Chromebook Plus) and without a lid
> (Scarlet / Acer Chromebook Tab 10).
> 
> This error got introduced when porting the feature from the downstream
> Chromium OS kernel to be upstreamed.
> 
> Fixes: cdd7950e7aa4 ("input: cros_ec_keyb: Add non-matrix buttons and switches")
> Cc: <stable@...r.kernel.org>
> Cc: Douglas Anderson <dianders@...omium.org>
> Cc: Enric Balletbo i Serra <enric.balletbo@...labora.com>
> Signed-off-by: Brian Norris <briannorris@...omium.org>

Applied, thank you.

> ---
>  drivers/input/keyboard/cros_ec_keyb.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/input/keyboard/cros_ec_keyb.c b/drivers/input/keyboard/cros_ec_keyb.c
> index 81be6f781f0b..d56001181598 100644
> --- a/drivers/input/keyboard/cros_ec_keyb.c
> +++ b/drivers/input/keyboard/cros_ec_keyb.c
> @@ -493,7 +493,8 @@ static int cros_ec_keyb_register_bs(struct cros_ec_keyb *ckdev)
>  	for (i = 0; i < ARRAY_SIZE(cros_ec_keyb_bs); i++) {
>  		const struct cros_ec_bs_map *map = &cros_ec_keyb_bs[i];
>  
> -		if (buttons & BIT(map->bit))
> +		if ((map->ev_type == EV_KEY && (buttons & BIT(map->bit))) ||
> +		    (map->ev_type == EV_SW && (switches & BIT(map->bit))))
>  			input_set_capability(idev, map->ev_type, map->code);
>  	}
>  
> -- 
> 2.19.1.930.g4563a0d9d0-goog
> 

-- 
Dmitry