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=-12.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 0B7D6C433E0 for ; Tue, 23 Feb 2021 00:01:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C8DEA64E41 for ; Tue, 23 Feb 2021 00:01:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231776AbhBWABj (ORCPT ); Mon, 22 Feb 2021 19:01:39 -0500 Received: from mail.kernel.org ([198.145.29.99]:55994 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231408AbhBWAB1 (ORCPT ); Mon, 22 Feb 2021 19:01:27 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 97E0360C41; Tue, 23 Feb 2021 00:00:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1614038446; bh=af3kVTgsG+nH3bM3IYnJBqeSQYehgcaCIygkIvqVjeQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=nV6TYhL/oZNC9ifaFgtV5DjQUEKW4ct/RZXzL5cEAO+OEiYaRVvJB6MnQTc1GgLDg ZxZPHOSv1bmmm50hjEKCBKAdJy06dDuQgJws05+gPJ7vhenuXz0IbFL9AHEcQCGmZu imEAdGj/OEhQSAKHAz3rHudTUwkOAJGTbcsmgQ3E4mnIeJk4ydl08iGkjwUVUAN1X+ gpuniD1QjbCS0WDVI9g2unaM1LUFoC9It+wtjRh0GXnNVsd+VoG5YBbI4/JwHcPTrq FRtTYoRRzhd2gk02YLalZuf1ZGsh62b0eufN0g4UGVYTpcrawf1WR9HZdvEwjFLc3p nD7cOeD11urKg== Date: Mon, 22 Feb 2021 17:00:45 -0700 From: Nathan Chancellor To: Simon Ser Cc: stylon.wang@amd.com, sunpeng.li@amd.com, Bhawanpreet.Lakha@amd.com, dri-devel@lists.freedesktop.org, Rodrigo.Siqueira@amd.com, linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, nicholas.kazlauskas@amd.com, airlied@linux.ie, aurabindo.pillai@amd.com, Souptick Joarder , daniel@ffwll.ch, bas@basnieuwenhuizen.nl, alexander.deucher@amd.com, harry.wentland@amd.com, christian.koenig@amd.com Subject: Re: [PATCH] drm/amdgpu/display: initialize the variable 'i' Message-ID: <20210223000045.GA4304@24bbad8f3778> References: <1614021931-4386-1-git-send-email-jrdr.linux@gmail.com> <32vjVDssCxltB75h5jHin2U3-cvNjmd_HFnRLiKohhbXkTfZea3hw2Knd80SgcHoyIFldMNwqh49t28hMBvta0HeWed1L0q_efLJ8QCgNw8=@emersion.fr> <20210222234457.GA36153@24bbad8f3778> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 22, 2021 at 11:50:06PM +0000, Simon Ser wrote: > On Tuesday, February 23rd, 2021 at 12:44 AM, Nathan Chancellor wrote: > > > On Mon, Feb 22, 2021 at 11:05:17PM +0000, Simon Ser wrote: > > > On Monday, February 22nd, 2021 at 8:25 PM, Souptick Joarder wrote: > > > > > > > >> drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:9804:38: > > > > >> warning: variable 'i' is uninitialized when used here > > > > >> [-Wuninitialized] > > > > timing = &edid->detailed_timings[i]; > > > > ^ > > > > drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:9714:7: > > > > note: initialize the variable 'i' to silence this warning > > > > int i; > > > > ^ > > > > = 0 > > > > 1 warning generated. > > > > > > > > Initialize the variable 'i'. > > > > > > Hm, I see this variable already initialized in the loop: > > > > > > for (i = 0; i < 4; i++) { > > > > > > This is the branch agd5f/drm-next. > > > > That is in the > > > > if (amdgpu_dm_connector->dc_sink->sink_signal == SIGNAL_TYPE_DISPLAY_PORT > > || amdgpu_dm_connector->dc_sink->sink_signal == SIGNAL_TYPE_EDP) { > > > > branch not the > > > > } else if (edid && amdgpu_dm_connector->dc_sink->sink_signal == SIGNAL_TYPE_HDMI_TYPE_A) { > > > > branch, where i is indeed used uninitialized like clang complains about. > > > > I am not at all familiar with the code so I cannot say if this fix is > > the proper one but it is definitely a legitimate issue. > > I think you have an outdated branch. In my checkout, i is not used in the first > branch, and is initialized in the second one. > > https://cgit.freedesktop.org/~agd5f/linux/tree/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c?h=drm-next#n9700 That branch is the outdated one: https://git.kernel.org/linus/a897913a819191550ab2fa2784d3c3ada3a096d3 Please see: https://gitlab.freedesktop.org/agd5f/linux/-/blob/amd-staging-drm-next/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c#L9854 It was introduced by commit f9b4f20c4777 ("drm/amd/display: Add Freesync HDMI support to DM"). Cheers, Nathan