From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f65.google.com ([74.125.82.65]:36638 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756649AbcBIN3x (ORCPT ); Tue, 9 Feb 2016 08:29:53 -0500 Received: by mail-wm0-f65.google.com with SMTP id 128so3424466wmz.3 for ; Tue, 09 Feb 2016 05:29:52 -0800 (PST) Subject: Re: [PATCH 4/6] drm: Fix treatment of drm_vblank_offdelay in drm_vblank_on() To: =?UTF-8?B?VmlsbGUgU3lyasOkbMOk?= , Daniel Vetter References: <1454894009-15466-1-git-send-email-mario.kleiner.de@gmail.com> <1454894009-15466-5-git-send-email-mario.kleiner.de@gmail.com> <20160209100618.GO11240@phenom.ffwll.local> <20160209111015.GJ23290@intel.com> Cc: dri-devel@lists.freedesktop.org, linux@bernd-steinhauser.de, stable@vger.kernel.org, michel@daenzer.net, vbabka@suse.cz, daniel.vetter@ffwll.ch, alexander.deucher@amd.com, christian.koenig@amd.com From: Mario Kleiner Message-ID: <56B9E9CD.8090609@gmail.com> Date: Tue, 9 Feb 2016 14:29:49 +0100 MIME-Version: 1.0 In-Reply-To: <20160209111015.GJ23290@intel.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: On 02/09/2016 12:10 PM, Ville Syrj�l� wrote: > On Tue, Feb 09, 2016 at 11:06:18AM +0100, Daniel Vetter wrote: >> On Mon, Feb 08, 2016 at 02:13:27AM +0100, Mario Kleiner wrote: >>> 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. >>> >>> Signed-off-by: Mario Kleiner >>> Cc: # 3.18+ >>> 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 >>> --- >>> drivers/gpu/drm/drm_irq.c | 4 ++-- >>> 1 file changed, 2 insertions(+), 2 deletions(-) >>> >>> diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c >>> index 5c27ad3..fb17c45 100644 >>> --- a/drivers/gpu/drm/drm_irq.c >>> +++ b/drivers/gpu/drm/drm_irq.c >>> @@ -1492,8 +1492,8 @@ void drm_vblank_on(struct drm_device *dev, unsigned int pipe) >>> * 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 || >>> + (!dev->vblank_disable_immediate && drm_vblank_offdelay > 0)) >> >> Hm, shouldn't we change this to only enable the vblank irq if we need it, >> i.e. offdelay == 0? For delayed disabling there's kinda no need to enable >> it superflously after a modeset, if userspace didn't yet ask for vblank >> timestamps. But then is was specifically added by Ville in cd19e52aee922, >> so I guess someone really wants this. > > IIRC what I wanted was to just re-enable the interrupt for the offdelay==0 > case. 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. > >> >> Reviewed-by: Daniel Vetter >> I can change that to offdelay==0 only, if you want. It was mostly about preserving what's there while at the same time fixing the important offdelay==0 user override. -mario >>> WARN_ON(drm_vblank_enable(dev, pipe)); >>> spin_unlock_irqrestore(&dev->vbl_lock, irqflags); >>> } >>> -- >>> 1.9.1 >>> >> >> -- >> Daniel Vetter >> Software Engineer, Intel Corporation >> http://blog.ffwll.ch > From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mario Kleiner Subject: Re: [PATCH 4/6] drm: Fix treatment of drm_vblank_offdelay in drm_vblank_on() Date: Tue, 9 Feb 2016 14:29:49 +0100 Message-ID: <56B9E9CD.8090609@gmail.com> References: <1454894009-15466-1-git-send-email-mario.kleiner.de@gmail.com> <1454894009-15466-5-git-send-email-mario.kleiner.de@gmail.com> <20160209100618.GO11240@phenom.ffwll.local> <20160209111015.GJ23290@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20160209111015.GJ23290@intel.com> Sender: stable-owner@vger.kernel.org To: =?UTF-8?B?VmlsbGUgU3lyasOkbMOk?= , Daniel Vetter Cc: dri-devel@lists.freedesktop.org, linux@bernd-steinhauser.de, stable@vger.kernel.org, michel@daenzer.net, vbabka@suse.cz, daniel.vetter@ffwll.ch, alexander.deucher@amd.com, christian.koenig@amd.com List-Id: dri-devel@lists.freedesktop.org On 02/09/2016 12:10 PM, Ville Syrj=E4l=E4 wrote: > On Tue, Feb 09, 2016 at 11:06:18AM +0100, Daniel Vetter wrote: >> On Mon, Feb 08, 2016 at 02:13:27AM +0100, Mario Kleiner wrote: >>> drm_vblank_offdelay can have three different types of values: >>> >>> < 0 is to be always treated the same as dev->vblank_disable_immedia= te >>> =3D 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. >>> >>> Signed-off-by: Mario Kleiner >>> Cc: # 3.18+ >>> 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 >>> --- >>> drivers/gpu/drm/drm_irq.c | 4 ++-- >>> 1 file changed, 2 insertions(+), 2 deletions(-) >>> >>> diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c >>> index 5c27ad3..fb17c45 100644 >>> --- a/drivers/gpu/drm/drm_irq.c >>> +++ b/drivers/gpu/drm/drm_irq.c >>> @@ -1492,8 +1492,8 @@ void drm_vblank_on(struct drm_device *dev, un= signed int pipe) >>> * 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) !=3D 0 || >>> - (!dev->vblank_disable_immediate && drm_vblank_offdelay =3D=3D= 0)) >>> + if (atomic_read(&vblank->refcount) !=3D 0 || drm_vblank_offdelay = =3D=3D 0 || >>> + (!dev->vblank_disable_immediate && drm_vblank_offdelay > 0)) >> >> Hm, shouldn't we change this to only enable the vblank irq if we nee= d it, >> i.e. offdelay =3D=3D 0? For delayed disabling there's kinda no need = to enable >> it superflously after a modeset, if userspace didn't yet ask for vbl= ank >> timestamps. But then is was specifically added by Ville in cd19e52ae= e922, >> so I guess someone really wants this. > > IIRC what I wanted was to just re-enable the interrupt for the offdel= ay=3D=3D0 > case. I think it just ended up as a mess due to changing some of the > semantics of offdelay<0 vs. offdelay=3D=3D0 vs. disable_immediate dur= ing the > review of the series. So yeah, given how drm_vblank_put() works now, = I'd > just make this check for offdelay=3D=3D0. > >> >> Reviewed-by: Daniel Vetter >> I can change that to offdelay=3D=3D0 only, if you want. It was mostly a= bout=20 preserving what's there while at the same time fixing the important=20 offdelay=3D=3D0 user override. -mario >>> WARN_ON(drm_vblank_enable(dev, pipe)); >>> spin_unlock_irqrestore(&dev->vbl_lock, irqflags); >>> } >>> -- >>> 1.9.1 >>> >> >> -- >> Daniel Vetter >> Software Engineer, Intel Corporation >> http://blog.ffwll.ch >