Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753463AbcCBAeq (ORCPT ); Tue, 1 Mar 2016 19:34:46 -0500 Received: from mail177-1.suw61.mandrillapp.com ([198.2.177.1]:27939 "EHLO mail177-1.suw61.mandrillapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756269AbcCAX5U (ORCPT ); Tue, 1 Mar 2016 18:57:20 -0500 From: Greg Kroah-Hartman Subject: [PATCH 4.4 232/342] drm: Fix treatment of drm_vblank_offdelay in drm_vblank_on() (v2) X-Mailer: git-send-email 2.7.2 To: Cc: Greg Kroah-Hartman , , Mario Kleiner , Daniel Vetter , , , , , , , Dave Airlie Message-Id: <20160301234535.419474625@linuxfoundation.org> In-Reply-To: <20160301234527.990448862@linuxfoundation.org> References: <20160301234527.990448862@linuxfoundation.org> X-Report-Abuse: Please forward a copy of this message, including all headers, to abuse@mandrill.com X-Report-Abuse: You can also report abuse here: http://mandrillapp.com/contact/abuse?id=30481620.e6aada45d89446e1ab116f46c461c8b4 X-Mandrill-User: md_30481620 Date: Tue, 01 Mar 2016 23:55:00 +0000 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2586 Lines: 64 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mario Kleiner commit bb74fc1bf3072bd3ab4ed5f43afd287a63baf2d7 upstream. drm_vblank_offdelay can have three different types of values: < 0 is to be always treated the same as dev->vblank_disable_immediate = 0 is to be treated as "never disable vblanks" > 0 is to be treated as disable immediate if kms driver wants it that way via dev->vblank_disable_immediate. Otherwise it is a disable timeout in msecs. This got broken in Linux 3.18+ for the implementation of drm_vblank_on. If the user specified a value of zero which should always reenable vblank irqs in this function, a kms driver could override the users choice by setting vblank_disable_immediate to true. This patch fixes the regression and keeps the user in control. v2: Only reenable vblank if there are clients left or the user requested to "never disable vblanks" via offdelay 0. Enabling vblanks even in the "delayed disable" case (offdelay > 0) was specifically added by Ville in commit cd19e52aee922 ("drm: Kick start vblank interrupts at drm_vblank_on()"), but after discussion it turns out that this was done by accident. Citing Ville: "I think it just ended up as a mess due to changing some of the semantics of offdelay<0 vs. offdelay==0 vs. disable_immediate during the review of the series. So yeah, given how drm_vblank_put() works now, I'd just make this check for offdelay==0." Signed-off-by: Mario Kleiner Reviewed-by: Daniel Vetter Cc: michel@daenzer.net Cc: vbabka@suse.cz Cc: ville.syrjala@linux.intel.com Cc: daniel.vetter@ffwll.ch Cc: dri-devel@lists.freedesktop.org Cc: alexander.deucher@amd.com Cc: christian.koenig@amd.com Signed-off-by: Dave Airlie Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/drm_irq.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -1494,8 +1494,7 @@ void drm_vblank_on(struct drm_device *de * re-enable interrupts if there are users left, or the * user wishes vblank interrupts to be enabled all the time. */ - if (atomic_read(&vblank->refcount) != 0 || - (!dev->vblank_disable_immediate && drm_vblank_offdelay == 0)) + if (atomic_read(&vblank->refcount) != 0 || drm_vblank_offdelay == 0) WARN_ON(drm_vblank_enable(dev, pipe)); spin_unlock_irqrestore(&dev->vbl_lock, irqflags); }