From patchwork Mon Jan 18 11:34:19 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 366098 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 6FA77C433E9 for ; Mon, 18 Jan 2021 11:39:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3388F223DB for ; Mon, 18 Jan 2021 11:39:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390510AbhARLjD (ORCPT ); Mon, 18 Jan 2021 06:39:03 -0500 Received: from mail.kernel.org ([198.145.29.99]:34108 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390474AbhARLiq (ORCPT ); Mon, 18 Jan 2021 06:38:46 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0DC562223E; Mon, 18 Jan 2021 11:37:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1610969875; bh=ImAx8VLNvSv8MYH4ZZXbLsF/zHT3Dgn5tGRGNHrsbAo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=L1QNEgcArIqTF/LdXLuq+l1kPHIQwKhrzrGswv/7PEu9IfA02eSf+EJ6OvphaMtZs s8rOyIK29/T5SZUvcI1QUIc4FdI26pwNc2aFie15DE2tlLTO/6A5HZXrJmtfMwvIvu tIpJcIhPvGZO+KWB2CaPaqfeoojt8+gqk6BTq4lM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Maarten Lankhorst , =?utf-8?b?VmlsbGUgU3lyasOkbMOk?= , Lyude Paul , Jani Nikula , Sasha Levin Subject: [PATCH 5.4 19/76] drm/i915/backlight: fix CPU mode backlight takeover on LPT Date: Mon, 18 Jan 2021 12:34:19 +0100 Message-Id: <20210118113341.913992596@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210118113340.984217512@linuxfoundation.org> References: <20210118113340.984217512@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jani Nikula [ Upstream commit bb83d5fb550bb7db75b29e6342417fda2bbb691c ] 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: Sasha Levin --- 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 bc14e9c0285a0..23edc1b8e43fa 100644 --- a/drivers/gpu/drm/i915/display/intel_panel.c +++ b/drivers/gpu/drm/i915/display/intel_panel.c @@ -1603,20 +1603,21 @@ 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_DEBUG_KMS("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); I915_WRITE(BLC_PWM_PCH_CTL1, pch_ctl1 | BLM_PCH_OVERRIDE_ENABLE); I915_WRITE(BLC_PWM_CPU_CTL2, 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; }