Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753294AbaJIIxT (ORCPT ); Thu, 9 Oct 2014 04:53:19 -0400 Received: from gw-1.arm.linux.org.uk ([78.32.30.217]:58319 "EHLO pandora.arm.linux.org.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750918AbaJIIxO (ORCPT ); Thu, 9 Oct 2014 04:53:14 -0400 Date: Thu, 9 Oct 2014 09:52:58 +0100 From: Russell King - ARM Linux To: Alexandre Courbot Cc: Andrzej Hajda , Inki Dae , Joonyoung Shim , Thierry Reding , linux-samsung-soc@vger.kernel.org, Daniel Vetter , Seung-Woo Kim , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Kyungmin Park , Kukjin Kim , Benjamin Gaignard , Ville =?iso-8859-1?Q?Syrj=E4l=E4?= , "linux-tegra@vger.kernel.org" Subject: Re: [PATCH] drm/exynos: fix vblank handling during dpms off Message-ID: <20141009085258.GI5182@n2100.arm.linux.org.uk> References: <542B9A0E.7020206@samsung.com> <1412151287-12845-1-git-send-email-a.hajda@samsung.com> <542D13CC.5000304@samsung.com> <542D2E7C.1020904@samsung.com> <542D3C96.7000400@samsung.com> <54362066.9000504@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <54362066.9000504@nvidia.com> User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 09, 2014 at 02:43:02PM +0900, Alexandre Courbot wrote: > But there might be another issue, which is that calls to > drm_vblank_get() will return -EINVAL if invoked between drm_blank_off > and drm_blank_on. Is this really the desired behavior? Can it at least > happen? If so, how are drivers supposed to react to this situation? I've not yet seen the commit which causes this problem, but I hope that drm_wait_vblank() isn't affected by this. In current mainline, drm_vblank_get() is used inside drm_wait_vblank(), which is called as a result of userspace calling DRM_IOCTL_WAIT_VBLANK. So, what is the effect of this change on user applications making use of the vblank wait ioctl - and is that change intended? -- FTTC broadband for 0.8mile line: currently at 9.5Mbps down 400kbps up according to speedtest.net. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/