Re: [PATCH] Xen Keyboard: don't advertise every key known to man

From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Phillip Susi <phill@thesusis.net>
Cc: xen-devel@lists.xenproject.org, linux-input@vger.kernel.org
Subject: Re: [PATCH] Xen Keyboard: don't advertise every key known to man
Date: Thu, 6 May 2021 13:26:48 -0700	[thread overview]
Message-ID: <YJRRCEJrQOwVymdP@google.com> (raw)
In-Reply-To: <20210506143654.17924-1-phill@thesusis.net>

On Thu, May 06, 2021 at 02:36:54PM +0000, Phillip Susi wrote:
> For reasons I still don't understand, the input subsystem allows
> input devices to advertise what keys they have, and adds this
> information to the modalias for the device.  The Xen Virtual
> Keyboard was advertising every known key, which resulted in a
> modalias string over 2 KiB in length, which caused uevents to
> fail with -ENOMEM ( when trying to add the modalias to the env ).
> Remove this advertisement.
> ---
>  drivers/input/misc/xen-kbdfront.c | 5 -----
>  1 file changed, 5 deletions(-)
> 
> diff --git a/drivers/input/misc/xen-kbdfront.c b/drivers/input/misc/xen-kbdfront.c
> index 4ff5cd2a6d8d..d4bd558afda9 100644
> --- a/drivers/input/misc/xen-kbdfront.c
> +++ b/drivers/input/misc/xen-kbdfront.c
> @@ -254,11 +254,6 @@ static int xenkbd_probe(struct xenbus_device *dev,
>  		kbd->id.product = 0xffff;
>  
>  		__set_bit(EV_KEY, kbd->evbit);
> -		for (i = KEY_ESC; i < KEY_UNKNOWN; i++)
> -			__set_bit(i, kbd->keybit);
> -		for (i = KEY_OK; i < KEY_MAX; i++)
> -			__set_bit(i, kbd->keybit);
> -

By doing this you are stopping delivery of all key events from this
device.

Thanks.

-- 
Dmitry