From patchwork Tue Oct 21 10:59:55 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Dheeraj Jamwal X-Patchwork-Id: 5123511 Return-Path: X-Original-To: patchwork-ltsi-dev@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 0C1DBC11AC for ; Tue, 21 Oct 2014 12:15:03 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 2828020148 for ; Tue, 21 Oct 2014 12:15:02 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0510B200E3 for ; Tue, 21 Oct 2014 12:15:01 +0000 (UTC) Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id 0893F15BC; Tue, 21 Oct 2014 11:16:08 +0000 (UTC) X-Original-To: ltsi-dev@lists.linuxfoundation.org Delivered-To: ltsi-dev@mail.linuxfoundation.org Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 8C2D0D29 for ; Tue, 21 Oct 2014 11:16:03 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by smtp1.linuxfoundation.org (Postfix) with ESMTP id 279971FAA9 for ; Tue, 21 Oct 2014 11:16:03 +0000 (UTC) Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga102.fm.intel.com with ESMTP; 21 Oct 2014 04:16:03 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,761,1406617200"; d="scan'208";a="617801992" Received: from ubuntu-desktop.png.intel.com ([10.221.122.25]) by fmsmga002.fm.intel.com with ESMTP; 21 Oct 2014 04:16:02 -0700 From: Dheeraj Jamwal To: ltsi-dev@lists.linuxfoundation.org Date: Tue, 21 Oct 2014 18:59:55 +0800 Message-Id: <1413889294-31328-996-git-send-email-dheerajx.s.jamwal@intel.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1413889294-31328-1-git-send-email-dheerajx.s.jamwal@intel.com> References: <1413889294-31328-1-git-send-email-dheerajx.s.jamwal@intel.com> MIME-Version: 1.0 X-Spam-Status: No, score=-5.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org Subject: [LTSI-dev] [PATCH 0995/1094] drm/i915: Draw a picture about video timings X-BeenThere: ltsi-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: "A list to discuss patches, development, and other things related to the LTSI project" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: ltsi-dev-bounces@lists.linuxfoundation.org Errors-To: ltsi-dev-bounces@lists.linuxfoundation.org X-Virus-Scanned: ClamAV using ClamSMTP From: Ville Syrjälä The docs are a bit lacking when it comes to describing when certain timing related events occur in the hardware. Draw a picture which tries to capture the most important ones. v2: Clarify a few details (Imre) v3: Add HSW+ HDMI scanline counter numbers Acked-by: Imre Deak Reviewed-by: Akash Goel Signed-off-by: Ville Syrjälä Reviewed-by: "Sourab Gupta " Signed-off-by: Daniel Vetter (cherry picked from commit f75f3746e801504531bffc9f92e1d4a271705f7e) Signed-off-by: Dheeraj Jamwal --- drivers/gpu/drm/i915/i915_irq.c | 50 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c index 16880cf..087e76b 100644 --- a/drivers/gpu/drm/i915/i915_irq.c +++ b/drivers/gpu/drm/i915/i915_irq.c @@ -740,6 +740,56 @@ i915_pipe_enabled(struct drm_device *dev, int pipe) } } +/* + * This timing diagram depicts the video signal in and + * around the vertical blanking period. + * + * Assumptions about the fictitious mode used in this example: + * vblank_start >= 3 + * vsync_start = vblank_start + 1 + * vsync_end = vblank_start + 2 + * vtotal = vblank_start + 3 + * + * start of vblank: + * latch double buffered registers + * increment frame counter (ctg+) + * generate start of vblank interrupt (gen4+) + * | + * | frame start: + * | generate frame start interrupt (aka. vblank interrupt) (gmch) + * | may be shifted forward 1-3 extra lines via PIPECONF + * | | + * | | start of vsync: + * | | generate vsync interrupt + * | | | + * ___xxxx___ ___xxxx___ ___xxxx___ ___xxxx___ ___xxxx___ ___xxxx + * . \hs/ . \hs/ \hs/ \hs/ . \hs/ + * ----va---> <-----------------vb--------------------> <--------va------------- + * | | <----vs-----> | + * -vbs-----> <---vbs+1---> <---vbs+2---> <-----0-----> <-----1-----> <-----2--- (scanline counter gen2) + * -vbs-2---> <---vbs-1---> <---vbs-----> <---vbs+1---> <---vbs+2---> <-----0--- (scanline counter gen3+) + * -vbs-2---> <---vbs-2---> <---vbs-1---> <---vbs-----> <---vbs+1---> <---vbs+2- (scanline counter hsw+ hdmi) + * | | | + * last visible pixel first visible pixel + * | increment frame counter (gen3/4) + * pixel counter = vblank_start * htotal pixel counter = 0 (gen3/4) + * + * x = horizontal active + * _ = horizontal blanking + * hs = horizontal sync + * va = vertical active + * vb = vertical blanking + * vs = vertical sync + * vbs = vblank_start (number) + * + * Summary: + * - most events happen at the start of horizontal sync + * - frame start happens at the start of horizontal blank, 1-4 lines + * (depending on PIPECONF settings) after the start of vblank + * - gen3/4 pixel and frame counter are synchronized with the start + * of horizontal active on the first line of vertical active + */ + static u32 i8xx_get_vblank_counter(struct drm_device *dev, int pipe) { /* Gen2 doesn't have a hardware frame counter */