From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753489AbdDJOBE (ORCPT ); Mon, 10 Apr 2017 10:01:04 -0400 Received: from mail-wr0-f195.google.com ([209.85.128.195]:36778 "EHLO mail-wr0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752518AbdDJOBC (ORCPT ); Mon, 10 Apr 2017 10:01:02 -0400 Subject: Re: [Xen-devel] [PATCH 1/2] xen, input: add xen-kbdfront module parameter for setting resolution To: Juergen Gross , linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, linux-input@vger.kernel.org References: <20170321171905.31584-1-jgross@suse.com> <20170321171905.31584-2-jgross@suse.com> <44a8ef04-53eb-df79-868e-96cc12302a78@suse.com> Cc: dmitry.torokhov@gmail.com From: Oleksandr Andrushchenko Message-ID: Date: Mon, 10 Apr 2017 17:00:49 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <44a8ef04-53eb-df79-868e-96cc12302a78@suse.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/10/2017 04:50 PM, Juergen Gross wrote: > On 10/04/17 15:44, Oleksandr Andrushchenko wrote: >> Hi, Juergen! >> >> On 03/21/2017 07:19 PM, Juergen Gross wrote: >>> Add a parameter for setting the resolution of xen-kbdfront in order to >>> be able to cope with a (virtual) frame buffer of arbitrary resolution. >>> >>> Signed-off-by: Juergen Gross >>> --- >>> drivers/input/misc/xen-kbdfront.c | 10 ++++++++-- >>> 1 file changed, 8 insertions(+), 2 deletions(-) >>> >>> diff --git a/drivers/input/misc/xen-kbdfront.c >>> b/drivers/input/misc/xen-kbdfront.c >>> index 3900875..2df5678 100644 >>> --- a/drivers/input/misc/xen-kbdfront.c >>> +++ b/drivers/input/misc/xen-kbdfront.c >>> @@ -41,6 +41,12 @@ struct xenkbd_info { >>> char phys[32]; >>> }; >>> +enum { KPARAM_WIDTH, KPARAM_HEIGHT, KPARAM_CNT }; >>> +static int size[KPARAM_CNT] = { XENFB_WIDTH, XENFB_HEIGHT }; >>> +module_param_array(size, int, NULL, 0444); >> is this by intention that you use 0444 here? >> It means read-only, thus one cannot change these, >> so what is the point of the module parameters then? > You can see the settings in sysfs. this is good so we can see actual width/height used by the pv driver > The values are settable via boot parameter. but then, if one has other values set in XenStore, these will/may be overridden, making it inconsistent, e.g. values loaded at start as module parameters (*size* array) is not going to be updated on XenbusStateInitWait/XenbusStateConnected. So, we'll end up with wrong parameters shown via sysfs one more question is why do we need module parameters if the same can be read from XenStore? > > Juergen Thank you, Oleksandr