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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 21E22C61DA4 for ; Sat, 18 Mar 2023 16:26:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229575AbjCRQ0Q (ORCPT ); Sat, 18 Mar 2023 12:26:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49890 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229648AbjCRQ0P (ORCPT ); Sat, 18 Mar 2023 12:26:15 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E114F1026E for ; Sat, 18 Mar 2023 09:25:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1679156725; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=RMLleG2DXcNogGAuAWxYrgTG9bG50WKJ62cIAjwjdNE=; b=a6JB5f00438iuVisdNyCoXZ2/4H11ClFxSe/p6HtvWdhdH/NSIccgZzl/QL1O3jenQjo/M StpGnyKQ+12mG6MyI0TV2aZ/Ks9VmyR2gf8q0bC5w3Ka4y7x6+Sa5Ah8CEdAzGEHOjxTIb t4+71vbnQeDjfFSxu/4D0L/6oBgu8I4= Received: from mail-ed1-f70.google.com (mail-ed1-f70.google.com [209.85.208.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-62-3wWA57ypMleOgdmr3c0b0g-1; Sat, 18 Mar 2023 12:25:23 -0400 X-MC-Unique: 3wWA57ypMleOgdmr3c0b0g-1 Received: by mail-ed1-f70.google.com with SMTP id b1-20020aa7dc01000000b004ad062fee5eso11670944edu.17 for ; Sat, 18 Mar 2023 09:25:23 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1679156722; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=RMLleG2DXcNogGAuAWxYrgTG9bG50WKJ62cIAjwjdNE=; b=GcA/f4Sy69M08t4IlfkP8IprlYN+T0XKfqwWquBlzBieBHwrbV6vjuqSsutCQm8gqk HLXuAN8iHctNP9iv98UgRqqHG0dPZ+DDlGJLxRTvnWkir3MdxWuOnQT6eTMwbfkOaYfo L9gMFY/obq7vt0yBTOfxFAmMdFrKrQlw8hwodM9S6Xrsyldp6tQcQu0aRA/gj9VNIBUn ZFFug2iBM353eVBiyeUdfaBo6aQ/kDpIBTJEsMpFpFJIT6mQqZ2QaP6yxqJs4M5LE3/A cGT1mhDFRWPX73G6v4jFpUiII1/Mzkm9pplO/2lX7Oax4fCj6vRn2o2n57ThtatfUHcd 9YYA== X-Gm-Message-State: AO0yUKVxmra+w/aAaBBa4jOFFNIc0PDKA8eGnn4ndNEK5uyVbOzoPz4W 4jvDfgdqwNrXm3doiQlsAlwrjLDN49VTY51tmZqFRrgpBvZ1e7wq6f/Su9lYwung62Ueo9GTE98 we5GVXHefFscUC55elxM8zOwL6v30K9k= X-Received: by 2002:a17:907:8690:b0:933:3a65:67ed with SMTP id qa16-20020a170907869000b009333a6567edmr2477137ejc.75.1679156721977; Sat, 18 Mar 2023 09:25:21 -0700 (PDT) X-Google-Smtp-Source: AK7set/0JZzssF+//gwBugYtJOfPoHdL9gBfMtdVZPgFd+DEMg4E7q1aCuABo4Gc7m0xJc3btkS1Og== X-Received: by 2002:a17:907:8690:b0:933:3a65:67ed with SMTP id qa16-20020a170907869000b009333a6567edmr2477124ejc.75.1679156721688; Sat, 18 Mar 2023 09:25:21 -0700 (PDT) Received: from ?IPV6:2001:1c00:c32:7800:5bfa:a036:83f0:f9ec? (2001-1c00-0c32-7800-5bfa-a036-83f0-f9ec.cable.dynamic.v6.ziggo.nl. [2001:1c00:c32:7800:5bfa:a036:83f0:f9ec]) by smtp.gmail.com with ESMTPSA id qq24-20020a17090720d800b008df7d2e122dsm2318909ejb.45.2023.03.18.09.25.20 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 18 Mar 2023 09:25:21 -0700 (PDT) Message-ID: Date: Sat, 18 Mar 2023 17:25:20 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.7.1 Subject: Re: [PATCH] input: alps: fix compatibility with -funsigned-char To: msizanoen , =?UTF-8?Q?Pali_Roh=c3=a1r?= , Dmitry Torokhov Cc: stable@vger.kernel.org, linux-input@vger.kernel.org, linux-kernel@vger.kernel.org References: <20230318144206.14309-1-msizanoen@qtmlabs.xyz> Content-Language: en-US, nl From: Hans de Goede In-Reply-To: <20230318144206.14309-1-msizanoen@qtmlabs.xyz> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org Hi, On 3/18/23 15:42, msizanoen wrote: > The AlpsPS/2 code previously relied on the assumption that `char` is a > signed type, which was true on x86 platforms (the only place where this > driver is used) before kernel 6.2. However, on 6.2 and later, this > assumption is broken due to the introduction of -funsigned-char as a new > global compiler flag. > > Fix this by explicitly specifying the signedness of `char` when sign > extending the values received from the device. > > Fixes: f3f33c677699 ("Input: alps - Rushmore and v7 resolution support") > Cc: stable@vger.kernel.org > Signed-off-by: msizanoen Thanks, patch looks good to me: Reviewed-by: Hans de Goede Regards, Hans > --- > drivers/input/mouse/alps.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/drivers/input/mouse/alps.c b/drivers/input/mouse/alps.c > index 989228b5a0a4..1c570d373b30 100644 > --- a/drivers/input/mouse/alps.c > +++ b/drivers/input/mouse/alps.c > @@ -2294,20 +2294,20 @@ static int alps_get_v3_v7_resolution(struct psmouse *psmouse, int reg_pitch) > if (reg < 0) > return reg; > > - x_pitch = (char)(reg << 4) >> 4; /* sign extend lower 4 bits */ > + x_pitch = (signed char)(reg << 4) >> 4; /* sign extend lower 4 bits */ > x_pitch = 50 + 2 * x_pitch; /* In 0.1 mm units */ > > - y_pitch = (char)reg >> 4; /* sign extend upper 4 bits */ > + y_pitch = (signed char)reg >> 4; /* sign extend upper 4 bits */ > y_pitch = 36 + 2 * y_pitch; /* In 0.1 mm units */ > > reg = alps_command_mode_read_reg(psmouse, reg_pitch + 1); > if (reg < 0) > return reg; > > - x_electrode = (char)(reg << 4) >> 4; /* sign extend lower 4 bits */ > + x_electrode = (signed char)(reg << 4) >> 4; /* sign extend lower 4 bits */ > x_electrode = 17 + x_electrode; > > - y_electrode = (char)reg >> 4; /* sign extend upper 4 bits */ > + y_electrode = (signed char)reg >> 4; /* sign extend upper 4 bits */ > y_electrode = 13 + y_electrode; > > x_phys = x_pitch * (x_electrode - 1); /* In 0.1 mm units */