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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 0C8F0C5518F for ; Tue, 4 Aug 2026 09:29:47 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id B84F210E94F; Tue, 4 Aug 2026 09:29:46 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="Aa6YWRP+"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.9]) by gabe.freedesktop.org (Postfix) with ESMTPS id 13B3310E65A; Tue, 4 Aug 2026 09:29:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1785835785; x=1817371785; h=from:subject:date:message-id:mime-version: content-transfer-encoding:to:cc; bh=3GlscK3lNx02BFsP++ibM8j6ZFvRGqpKlr5CF1uQT0w=; b=Aa6YWRP+5wCqyye1WNL1foVDMj+AA/5HxtQ3ft+9tcCf1dUgQ/K6Vja6 u9keornY1BHXVwOEvovajDiHtkC6jHTjGSBE2o7xC5OBt9AQER9t679RS lYxH9em2syorMLnPlu8OQG/s0Nl3a0DkKMEuMi8TzqA/yfiueZh2TE7fb p/EF2oOiG6tdz5GMqj69GkFSfTVFVZ8zMHy9/Z3egGul8XEv4cMmFZYhv dvDTuhUeIKCL7HE9xpYcBLJE1SoujV4joYFahYtu09oqsFREp2tx3Et3M v6rTrkam+GfjoN9hQuBjXmpwCi33VFukVZqiGZSQpCly/q5eVVo3S2pck A==; X-CSE-ConnectionGUID: 0BdnBZD9SPuVx9bA5gOO/Q== X-CSE-MsgGUID: oLu77guURTatlIuTbS2NOA== X-IronPort-AV: E=McAfee;i="6800,10657,11864"; a="97034039" X-IronPort-AV: E=Sophos;i="6.25,204,1779174000"; d="scan'208";a="97034039" Received: from orviesa006.jf.intel.com ([10.64.159.146]) by fmvoesa103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Aug 2026 02:29:44 -0700 X-CSE-ConnectionGUID: 0zzZfYfgQUiuutbyCUUNIQ== X-CSE-MsgGUID: q+7kfPdfTquUcTxBrpVEgg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,204,1779174000"; d="scan'208";a="259669116" Received: from srr4-3-linux-106-armuthy.iind.intel.com ([10.190.238.56]) by orviesa006.jf.intel.com with ESMTP; 04 Aug 2026 02:29:42 -0700 From: Arun R Murthy Subject: [PATCH 0/2] cdclk mismatch with sw/hw Date: Tue, 04 Aug 2026 14:58:29 +0530 Message-Id: <20260804-cdclk-v1-0-484864b1aafd@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-B4-Tracking: v=1; b=H4sIAL2wcWoC/6tWKk4tykwtVrJSqFYqSi3LLM7MzwNyDHUUlJIzE vPSU3UzU4B8JSMDIzMDCwMT3eSU5JxsXctU87S0ZHPDNAujRCWg2oKi1LTMCrA50bG1tQBBedh xVwAAAA== X-Change-ID: 20260804-cdclk-9e7ffc71f82a To: intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org Cc: Jani Nikula , Arun R Murthy , =?utf-8?q?Polo-Fran=C3=A7ois_Poli?= X-Mailer: b4 0.15-dev X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" With 4k eDP panel and an external DP, cdclk sw/hw state mismatch warnings are observed along with cdclk mismatch on DC6 exit is also observed and eventually FIFO underrun. On boot, skl_cdclk_init_hw()->skl_sanitize_cdclk() decides to use the pre-OS cdclk leading to programming a very low cdclk that doesnt satisfy the pipes requirement. This leads to FIFO underrun. Also this programmed and the sw calculated cdclk mismatches and on every dc state exit warnings are thrown. In this series the cdclk is programmed to max instead of 0, and then the first modeset will bring it back to the required/calculated. Signed-off-by: Arun R Murthy --- Arun R Murthy (2): drm/i915/display: Seed skl_cdclk_init_hw() with SKU-max, not zero drm/i915/display: Reconcile cdclk SW state with HW on DC-off exit drivers/gpu/drm/i915/display/intel_cdclk.c | 65 +++++++++++++++++++++- drivers/gpu/drm/i915/display/intel_cdclk.h | 2 + .../drm/i915/display/intel_display_power_well.c | 1 + 3 files changed, 67 insertions(+), 1 deletion(-) --- base-commit: 0377b35cbeef071dfeed06ccadc0d7607eccaa64 change-id: 20260804-cdclk-9e7ffc71f82a Best regards, -- Arun R Murthy