From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4E702C43215 for ; Wed, 27 Nov 2019 21:45:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 25EBF2154A for ; Wed, 27 Nov 2019 21:45:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574891137; bh=GQdssR5vvChor4Ev4t2/5349FPN4oSbrjLFcBctu+Y0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=gYU84pRW+Jd/UGot7V6nofciwyBdD3qJrIts51omLWLo3jS2taYT1J5fmh+hwnbW7 c5OnBRqkLeIcccY0ODFqhG5PQ6SturScuEKnHqcK5twFBxf3sXrntg5YcxifsLc3J8 DprFQEPlZ00Y2ePaLfd25XYRgM7K6/8PeiS4Zxzc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727872AbfK0Uf1 (ORCPT ); Wed, 27 Nov 2019 15:35:27 -0500 Received: from mail.kernel.org ([198.145.29.99]:36666 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727848AbfK0Uf0 (ORCPT ); Wed, 27 Nov 2019 15:35:26 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E8CC02154A; Wed, 27 Nov 2019 20:35:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574886926; bh=GQdssR5vvChor4Ev4t2/5349FPN4oSbrjLFcBctu+Y0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NIOJToz7rGmbbp5VMWQpGixnUp6+em0zROVAqfQDNAjYx8qIVpB4E0it5+1BevXRH Ww+PFTOVc/aDQ7y8oZo38C0X2DLGCTOPkwmRrmdfmjwZhmGcbpFDkcUJsPdbpVgwEC iW2NAxcJWer/fEn5medo9dd/Stb3oNhJWir7gnjg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mattias Jacobsson <2pi@mok.nu>, Sasha Levin Subject: [PATCH 4.4 046/132] USB: misc: appledisplay: fix backlight update_status return code Date: Wed, 27 Nov 2019 21:30:37 +0100 Message-Id: <20191127202942.227536708@linuxfoundation.org> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191127202857.270233486@linuxfoundation.org> References: <20191127202857.270233486@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Mattias Jacobsson <2pi@mok.nu> [ Upstream commit 090158555ff8d194a98616034100b16697dd80d0 ] Upon success the update_status handler returns a positive number corresponding to the number of bytes transferred by usb_control_msg. However the return code of the update_status handler should indicate if an error occurred(negative) or how many bytes of the user's input to sysfs that was consumed. Return code zero indicates all bytes were consumed. The bug can for example result in the update_status handler being called twice, the second time with only the "unconsumed" part of the user's input to sysfs. Effectively setting an incorrect brightness. Change the update_status handler to return zero for all successful transactions and forward usb_control_msg's error code upon failure. Signed-off-by: Mattias Jacobsson <2pi@mok.nu> Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/usb/misc/appledisplay.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/usb/misc/appledisplay.c b/drivers/usb/misc/appledisplay.c index 993f4da065c3a..dabd1077d03c4 100644 --- a/drivers/usb/misc/appledisplay.c +++ b/drivers/usb/misc/appledisplay.c @@ -161,8 +161,11 @@ static int appledisplay_bl_update_status(struct backlight_device *bd) pdata->msgdata, 2, ACD_USB_TIMEOUT); mutex_unlock(&pdata->sysfslock); - - return retval; + + if (retval < 0) + return retval; + else + return 0; } static int appledisplay_bl_get_brightness(struct backlight_device *bd) -- 2.20.1