From patchwork Wed Dec 6 22:47:37 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dhinakaran Pandiyan X-Patchwork-Id: 10097309 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 6697560327 for ; Wed, 6 Dec 2017 22:48:20 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 599B029B30 for ; Wed, 6 Dec 2017 22:48:20 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4DC5829BAA; Wed, 6 Dec 2017 22:48:20 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=unavailable version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id E155729B30 for ; Wed, 6 Dec 2017 22:48:19 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id EE1566E1DB; Wed, 6 Dec 2017 22:48:14 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by gabe.freedesktop.org (Postfix) with ESMTPS id 88D3A89F33; Wed, 6 Dec 2017 22:48:13 +0000 (UTC) Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 06 Dec 2017 14:48:12 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.45,369,1508828400"; d="scan'208";a="11207233" Received: from dk-thinkpad-x260.jf.intel.com (HELO localhost.localdomain) ([10.54.75.38]) by fmsmga001.fm.intel.com with ESMTP; 06 Dec 2017 14:48:12 -0800 From: Dhinakaran Pandiyan To: intel-gfx@lists.freedesktop.org Subject: [PATCH 1/5] drm/vblank: Do not update vblank counts if vblanks are already disabled. Date: Wed, 6 Dec 2017 14:47:37 -0800 Message-Id: <20171206224741.8600-1-dhinakaran.pandiyan@intel.com> X-Mailer: git-send-email 2.11.0 Cc: Daniel Vetter , Dhinakaran Pandiyan , dri-devel@lists.freedesktop.org, Rodrigo Vivi X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP Updating the vblank counts requires register reads and these reads may not return meaningful values after the vblank interrupts are disabled as the device may go to low power state. An additional change would be to allow the driver to save the vblank counts before entering a low power state, but that's for the future. Also, disable vblanks after reading the HW counter in the case where _crtc_vblank_off() is disabling vblanks. Signed-off-by: Dhinakaran Pandiyan --- drivers/gpu/drm/drm_vblank.c | 23 +++++++++-------------- 1 file changed, 9 insertions(+), 14 deletions(-) diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c index 32d9bcf5be7f..7eee82c06ed8 100644 --- a/drivers/gpu/drm/drm_vblank.c +++ b/drivers/gpu/drm/drm_vblank.c @@ -347,23 +347,14 @@ void drm_vblank_disable_and_save(struct drm_device *dev, unsigned int pipe) spin_lock_irqsave(&dev->vblank_time_lock, irqflags); /* - * Only disable vblank interrupts if they're enabled. This avoids - * calling the ->disable_vblank() operation in atomic context with the - * hardware potentially runtime suspended. - */ - if (vblank->enabled) { - __disable_vblank(dev, pipe); - vblank->enabled = false; - } - - /* - * Always update the count and timestamp to maintain the + * Update the count and timestamp to maintain the * appearance that the counter has been ticking all along until * this time. This makes the count account for the entire time * between drm_crtc_vblank_on() and drm_crtc_vblank_off(). */ drm_update_vblank_count(dev, pipe, false); - + __disable_vblank(dev, pipe); + vblank->enabled = false; spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags); } @@ -1122,8 +1113,12 @@ void drm_crtc_vblank_off(struct drm_crtc *crtc) pipe, vblank->enabled, vblank->inmodeset); /* Avoid redundant vblank disables without previous - * drm_crtc_vblank_on(). */ - if (drm_core_check_feature(dev, DRIVER_ATOMIC) || !vblank->inmodeset) + * drm_crtc_vblank_on() and only disable them if they're enabled. This + * avoids calling the ->disable_vblank() operation in atomic context + * with the hardware potentially runtime suspended. + */ + if ((drm_core_check_feature(dev, DRIVER_ATOMIC) || !vblank->inmodeset) && + vblank->enabled) drm_vblank_disable_and_save(dev, pipe); wake_up(&vblank->queue);