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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 D7FA1C433E0 for ; Mon, 11 Jan 2021 10:04:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 83D34221E3 for ; Mon, 11 Jan 2021 10:04:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728701AbhAKKEW convert rfc822-to-8bit (ORCPT ); Mon, 11 Jan 2021 05:04:22 -0500 Received: from mga12.intel.com ([192.55.52.136]:47678 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728531AbhAKKEV (ORCPT ); Mon, 11 Jan 2021 05:04:21 -0500 IronPort-SDR: g3J2nrXZQJDSgXCh2dL9sp9zwv5/YC8hEk8hv67z/t+On/HQb50cmBKMThoKkBQYZanzj9dsm/ 3aOs/ssp6iJw== X-IronPort-AV: E=McAfee;i="6000,8403,9860"; a="157017399" X-IronPort-AV: E=Sophos;i="5.79,338,1602572400"; d="scan'208";a="157017399" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Jan 2021 02:03:38 -0800 IronPort-SDR: b1DS422JqFycV3AofEy30Cu/snFqqIKdPFCjqP26gtp0i0PTDW0KVxX2rm/pUGWZJowbXvI9v6 Dgn+nshNG1dA== X-IronPort-AV: E=Sophos;i="5.79,338,1602572400"; d="scan'208";a="380959021" Received: from libresli-mobl1.ger.corp.intel.com (HELO localhost) ([10.213.207.39]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Jan 2021 02:03:35 -0800 From: Jani Nikula To: lyude@redhat.com, intel-gfx@lists.freedesktop.org Cc: Maarten Lankhorst , Ville =?utf-8?B?U3lyasOkbMOk?= , stable@vger.kernel.org Subject: Re: [PATCH] drm/i915/backlight: fix CPU mode backlight takeover on LPT In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20210108152841.6944-1-jani.nikula@intel.com> Date: Mon, 11 Jan 2021 12:03:33 +0200 Message-ID: <875z43yemi.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Fri, 08 Jan 2021, Lyude Paul wrote: > Reviewed-by: Lyude Paul > > Let me know when you've pushed this upstream and I'll go ahead and send out a > rebased version of my backlight series. Pushed, thanks for the review. I'm hoping to do more review of the series today, so please hold off on actually sending the rebased version for a bit longer. BR, Jani. > > On Fri, 2021-01-08 at 17:28 +0200, Jani Nikula wrote: >> The pch_get_backlight(), lpt_get_backlight(), and lpt_set_backlight() >> functions operate directly on the hardware registers. If inverting the >> value is needed, using intel_panel_compute_brightness(), it should only >> be done in the interface between hardware registers and >> panel->backlight.level. >> >> The CPU mode takeover code added in commit 5b1ec9ac7ab5 >> ("drm/i915/backlight: Fix backlight takeover on LPT, v3.") reads the >> hardware register and converts to panel->backlight.level correctly, >> however the value written back should remain in the hardware register >> "domain". >> >> This hasn't been an issue, because GM45 machines are the only known >> users of i915.invert_brightness and the brightness invert quirk, and >> without one of them no conversion is made. It's likely nobody's ever hit >> the problem. >> >> Fixes: 5b1ec9ac7ab5 ("drm/i915/backlight: Fix backlight takeover on LPT, v3.") >> Cc: Maarten Lankhorst >> Cc: Ville Syrjälä >> Cc: Lyude Paul >> Cc: # v5.1+ >> Signed-off-by: Jani Nikula >> --- >>  drivers/gpu/drm/i915/display/intel_panel.c | 9 +++++---- >>  1 file changed, 5 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/gpu/drm/i915/display/intel_panel.c >> b/drivers/gpu/drm/i915/display/intel_panel.c >> index 67f81ae995c4..7a4239d1c241 100644 >> --- a/drivers/gpu/drm/i915/display/intel_panel.c >> +++ b/drivers/gpu/drm/i915/display/intel_panel.c >> @@ -1649,16 +1649,13 @@ static int lpt_setup_backlight(struct intel_connector >> *connector, enum pipe unus >>                 val = pch_get_backlight(connector); >>         else >>                 val = lpt_get_backlight(connector); >> -       val = intel_panel_compute_brightness(connector, val); >> -       panel->backlight.level = clamp(val, panel->backlight.min, >> -                                      panel->backlight.max); >>   >>         if (cpu_mode) { >>                 drm_dbg_kms(&dev_priv->drm, >>                             "CPU backlight register was enabled, switching to >> PCH override\n"); >>   >>                 /* Write converted CPU PWM value to PCH override register */ >> -               lpt_set_backlight(connector->base.state, panel- >> >backlight.level); >> +               lpt_set_backlight(connector->base.state, val); >>                 intel_de_write(dev_priv, BLC_PWM_PCH_CTL1, >>                                pch_ctl1 | BLM_PCH_OVERRIDE_ENABLE); >>   >> @@ -1666,6 +1663,10 @@ static int lpt_setup_backlight(struct intel_connector >> *connector, enum pipe unus >>                                cpu_ctl2 & ~BLM_PWM_ENABLE); >>         } >>   >> +       val = intel_panel_compute_brightness(connector, val); >> +       panel->backlight.level = clamp(val, panel->backlight.min, >> +                                      panel->backlight.max); >> + >>         return 0; >>  } >>   -- Jani Nikula, Intel Open Source Graphics Center