From patchwork Fri Dec 4 08:18:44 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Gupta, Anshuman" X-Patchwork-Id: 11951075 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=-11.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,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 9025FC433FE for ; Fri, 4 Dec 2020 08:32:38 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2AA9922581 for ; Fri, 4 Dec 2020 08:32:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2AA9922581 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id A05EB6E13C; Fri, 4 Dec 2020 08:32:37 +0000 (UTC) Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by gabe.freedesktop.org (Postfix) with ESMTPS id 0C8256E135 for ; Fri, 4 Dec 2020 08:32:36 +0000 (UTC) IronPort-SDR: 3CQdwcwe1yFVvHPlpGOLBhIn6hkEX+P4D2J+J8cx4NZGOdnLCbck5jODdQ45pxhw3qGqRMWKUC gZiyJnH6BaeQ== X-IronPort-AV: E=McAfee;i="6000,8403,9824"; a="169840833" X-IronPort-AV: E=Sophos;i="5.78,392,1599548400"; d="scan'208";a="169840833" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Dec 2020 00:32:35 -0800 IronPort-SDR: 0zLC0RlL6j4COljRcCgQpvRV5UwwS24H5o+HHF4g9lYwJkntquB1VQ+KvByeVJUI1KfD5peguy nFRBRzt9XS7A== X-IronPort-AV: E=Sophos;i="5.78,392,1599548400"; d="scan'208";a="362110811" Received: from genxfsim-desktop.iind.intel.com ([10.223.74.178]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Dec 2020 00:32:32 -0800 From: Anshuman Gupta To: intel-gfx@lists.freedesktop.org Date: Fri, 4 Dec 2020 13:48:44 +0530 Message-Id: <20201204081845.26528-1-anshuman.gupta@intel.com> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH 0/1] Display glitches fixes X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" TGL chrome-OS platform has observed display glitches while display brightness is being changed rapidly. It creates a scenario where brightness is being changed simultaneously with display flips updates in different threads. Brightness update requires pps_lock, current pps_lock implementation requires to get AUX power domain, which triggers DC3CO disallow/allow sequence being async with display flips. This triggers a race between dc3co exit delay and display flip, and potentially causing a display glitch due to some display register being programmed before completing dc3co exit delay. Exactly which register programming causing this glitch is still being work in progressed. This patch adds a optimization to avoid unnecessary "DC off" power well enable/disable(D3CO disallow/allow) noise around brightness update. This patch helps to remove the display glitch in case of simultaneous brightness update and display flips. Anshuman Gupta (1): drm/i915/dp: optimize pps_lock wherever required drivers/gpu/drm/i915/display/intel_dp.c | 47 +++++++++++++++++++++++-- 1 file changed, 45 insertions(+), 2 deletions(-)