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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 D2686C4332B for ; Mon, 18 Jan 2021 18:42:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A9A9722C9E for ; Mon, 18 Jan 2021 18:42:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390735AbhARSmA (ORCPT ); Mon, 18 Jan 2021 13:42:00 -0500 Received: from mail.kernel.org ([198.145.29.99]:34192 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390686AbhARLlI (ORCPT ); Mon, 18 Jan 2021 06:41:08 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 208952245C; Mon, 18 Jan 2021 11:40:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1610970044; bh=o4CJEhv0q6H7UNfe5Vugtt8kugalayN7/GUJluN/pKA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Jx7KuDIqcihQLqsVEDeuHMZEiFwYbnT0f91YvlGGzgpbY8WTCMQgUBZyXElrsCsGT 3im2hTqamLILPSYcq+zjR3pJiOFV0cWMF5xkDz29IqQs2VsNhB93ImB79joUB1kdth PlEaxq8ufSdwMljqeR1N//tQnfHkAFYOYSf1ZfeE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Maarten Lankhorst , =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= , Lyude Paul , Jani Nikula Subject: [PATCH 5.10 014/152] drm/i915/backlight: fix CPU mode backlight takeover on LPT Date: Mon, 18 Jan 2021 12:33:09 +0100 Message-Id: <20210118113353.452774942@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210118113352.764293297@linuxfoundation.org> References: <20210118113352.764293297@linuxfoundation.org> User-Agent: quilt/0.66 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 From: Jani Nikula commit bb83d5fb550bb7db75b29e6342417fda2bbb691c upstream. 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+ Reviewed-by: Lyude Paul Signed-off-by: Jani Nikula Link: https://patchwork.freedesktop.org/patch/msgid/20210108152841.6944-1-jani.nikula@intel.com (cherry picked from commit 0d4ced1c5bfe649196877d90442d4fd618e19153) Signed-off-by: Jani Nikula Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/i915/display/intel_panel.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) --- a/drivers/gpu/drm/i915/display/intel_panel.c +++ b/drivers/gpu/drm/i915/display/intel_panel.c @@ -1650,16 +1650,13 @@ static int lpt_setup_backlight(struct in 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); @@ -1667,6 +1664,10 @@ static int lpt_setup_backlight(struct in 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; }