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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E1113C433EF for ; Mon, 18 Oct 2021 08:57:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BB3C260F9E for ; Mon, 18 Oct 2021 08:57:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231458AbhJRI72 (ORCPT ); Mon, 18 Oct 2021 04:59:28 -0400 Received: from mga03.intel.com ([134.134.136.65]:35106 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231190AbhJRI7X (ORCPT ); Mon, 18 Oct 2021 04:59:23 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10140"; a="228153348" X-IronPort-AV: E=Sophos;i="5.85,381,1624345200"; d="scan'208";a="228153348" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Oct 2021 01:57:11 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.85,381,1624345200"; d="scan'208";a="443325319" Received: from stinkbox.fi.intel.com (HELO stinkbox) ([10.237.72.171]) by orsmga006.jf.intel.com with SMTP; 18 Oct 2021 01:57:06 -0700 Received: by stinkbox (sSMTP sendmail emulation); Mon, 18 Oct 2021 11:57:06 +0300 Date: Mon, 18 Oct 2021 11:57:06 +0300 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: luo penghao Cc: Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , David Airlie , Daniel Vetter , Stephen Rothwell , intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, luo penghao , Zeal Robot Subject: Re: [PATCH linux-next] drm/i915/display: Remove unused variable and its assignment. Message-ID: References: <20211018084331.851975-1-luo.penghao@zte.com.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20211018084331.851975-1-luo.penghao@zte.com.cn> X-Patchwork-Hint: comment Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 18, 2021 at 08:43:31AM +0000, luo penghao wrote: > Variable is not used in functions, and its assignment is redundant too. > So it should be deleted. > > The clang_analyzer complains as follows: > > drivers/gpu/drm/i915/display/intel_dpll.c:1653:2 warning: > Value stored to 'bestm1' is never read. > > drivers/gpu/drm/i915/display/intel_dpll.c:1651:2 warning: > Value stored to 'bestn' is never read. > > Reported-by: Zeal Robot > Signed-off-by: luo penghao > --- > drivers/gpu/drm/i915/display/intel_dpll.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_dpll.c b/drivers/gpu/drm/i915/display/intel_dpll.c > index b84ed4a..28b1616 100644 > --- a/drivers/gpu/drm/i915/display/intel_dpll.c > +++ b/drivers/gpu/drm/i915/display/intel_dpll.c > @@ -1644,13 +1644,11 @@ static void chv_prepare_pll(const struct intel_crtc_state *crtc_state) > enum pipe pipe = crtc->pipe; > enum dpio_channel port = vlv_pipe_to_channel(pipe); > u32 loopfilter, tribuf_calcntr; > - u32 bestn, bestm1, bestm2, bestp1, bestp2, bestm2_frac; > + u32 bestm2, bestp1, bestp2, bestm2_frac; > u32 dpio_val; > int vco; > > - bestn = crtc_state->dpll.n; This one we could use. For some reason we hardcode it to 1 now, which is correct for our use cases but I don't really see a reason to hardcode it here. We are supposed to calculate it correctly after all, and chv_crtc_clock_get() also just blindly reads it out. > bestm2_frac = crtc_state->dpll.m2 & 0x3fffff; > - bestm1 = crtc_state->dpll.m1; This one is a bit trickier since I don't think the spec even gives us other values. But we could assert that it's correct. Some something along these lines I think would be best: + drm_WARN_ON(&dev_priv->drm, bestm1 != 2); vlv_dpio_write(dev_priv, pipe, CHV_PLL_DW1(port), DPIO_CHV_M1_DIV_BY_2 | - 1 << DPIO_CHV_N_DIV_SHIFT); + bestn << DPIO_CHV_N_DIV_SHIFT); -- Ville Syrjälä Intel