From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8162935AC18; Fri, 1 May 2026 20:19:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777666752; cv=none; b=HazbhsQL/uiyOCcIxsD+InaxXK5BjJJh5BCk3SC99hnVLS2kqNmqy0MLwtopnbS562a89QWTA+r+khAal+TVvWWnHDglFpDEHXRlAHNlVkmRpBcseLghfLPPv80XafhfRKxB4yYQ/kbIQa95CHciHvbB3Ft7XMhv3qoBYlwdpVo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777666752; c=relaxed/simple; bh=nTjZPSq8DBGTmtRgO55BiuONxSkZofggTHq8jvdoUmg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ZTZI6lCvIL3yLgwR+DzCfogk5K4mLyyk2RFpk/tPfz1tUQ0BCOHOIc1UlXNttpfPSMy7gHL4nruORnLyuo+aFHepWFNj7+qvxxh+WUxqc/+xjOtEaC4l6HnmaWGsw3W6Gn5x0W4PYFUmMeNvD4X0IqNA2s84dYCDFk4rjsVKBOg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=QhnIgNjQ; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="QhnIgNjQ" Received: from killaraus.ideasonboard.com (2001-14ba-703d-e500--2a1.rev.dnainternet.fi [IPv6:2001:14ba:703d:e500::2a1]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 0662E379; Fri, 1 May 2026 22:17:22 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1777666643; bh=nTjZPSq8DBGTmtRgO55BiuONxSkZofggTHq8jvdoUmg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=QhnIgNjQgi5FyiBaC6epUhdaXRIqM9ZC9nLt/3+8mph0qLiV+/O3kIQOm/RMXjhV4 n5KebhU+BX0DpXMRDYuFcUX2TpvHTCMsWyESXxJVcYDVjbkOJ0rCSPqkklox0mZK4P yGzPqF+y/T670DoHjt09RGakaujlNp4zG7HaIlPc= Date: Fri, 1 May 2026 23:19:06 +0300 From: Laurent Pinchart To: Ricardo Ribalda Cc: Mauro Carvalho Chehab , Sakari Ailus , Hans Verkuil , Nas Chung , Jackson Lee , Bingbu Cao , Tianshu Qiu , Greg Kroah-Hartman , Keke Li , Yong Zhi , Jacopo Mondi , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, linux-staging@lists.linux.dev, Mauro Carvalho Chehab Subject: Re: [PATCH v2 2/6] media: i2c: mt9p031: Rewrite a bitwise mask Message-ID: <20260501201906.GA488660@killaraus.ideasonboard.com> References: <20260501-smatch-7-1-v2-0-a2fcfb2531ac@chromium.org> <20260501-smatch-7-1-v2-2-a2fcfb2531ac@chromium.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20260501-smatch-7-1-v2-2-a2fcfb2531ac@chromium.org> On Fri, May 01, 2026 at 11:32:47AM +0000, Ricardo Ribalda wrote: > The current code makes smatch a bit uncomfortable: > drivers/media/i2c/mt9p031.c:799 mt9p031_s_ctrl() warn: assigning (-1952) to unsigned variable 'data' > > Probably because smatch is not clever enough (yet). Do a simple rewrite > to make sure that smatch understands what we are doing here. > > Signed-off-by: Ricardo Ribalda > --- > drivers/media/i2c/mt9p031.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/media/i2c/mt9p031.c b/drivers/media/i2c/mt9p031.c > index ea5d43d925ff..5c9dff030b4d 100644 > --- a/drivers/media/i2c/mt9p031.c > +++ b/drivers/media/i2c/mt9p031.c > @@ -795,7 +795,7 @@ static int mt9p031_s_ctrl(struct v4l2_ctrl *ctrl) > ctrl->val &= ~1; > data = (1 << 6) | (ctrl->val >> 1); > } else { > - ctrl->val &= ~7; > + ctrl->val -= ctrl->val % 8; > data = ((ctrl->val - 64) << 5) | (1 << 6) | 32; I'd still like to keep the ~7 (and, while at it, making the register computation easier to read). I previously proposed ctrl->val &= ~7; data = (ctrl->val - 64) >> 3; data = (data << 8) | (1 << 6) | 32; which didn't quite appease smatch. We could use an explicit mask: ctrl->val &= ~7; data = ((ctrl->val - 64) >> 3) & 0xff; data = (data << 8) | (1 << 6) | 32; > } > > -- Regards, Laurent Pinchart