From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753964AbcCGW5L (ORCPT ); Mon, 7 Mar 2016 17:57:11 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:39373 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932554AbcCGWyk (ORCPT ); Mon, 7 Mar 2016 17:54:40 -0500 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Mario Kleiner , michel@daenzer.net, vbabka@suse.cz, ville.syrjala@linux.intel.com, daniel.vetter@ffwll.ch, dri-devel@lists.freedesktop.org, alexander.deucher@amd.com, christian.koenig@amd.com, Dave Airlie , Kamal Mostafa Subject: [PATCH 4.2.y-ckt 170/273] drm: Fix treatment of drm_vblank_offdelay in drm_vblank_on() (v2) Date: Mon, 7 Mar 2016 14:49:21 -0800 Message-Id: <1457391064-6660-171-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 2.7.0 In-Reply-To: <1457391064-6660-1-git-send-email-kamal@canonical.com> References: <1457391064-6660-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 4.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.2.8-ckt5 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ 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: Kamal Mostafa --- drivers/gpu/drm/drm_irq.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index b50fa0a..6447b48 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -1338,8 +1338,7 @@ void drm_vblank_on(struct drm_device *dev, int crtc) * 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, crtc)); spin_unlock_irqrestore(&dev->vbl_lock, irqflags); } -- 2.7.0