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 <mario.kleiner.de@xxxxxxxxx> > > Cc: <stable@xxxxxxxxxxxxxxx> # 3.18+ > > Cc: michel@xxxxxxxxxxx > > Cc: vbabka@xxxxxxx > > Cc: ville.syrjala@xxxxxxxxxxxxxxx > > Cc: daniel.vetter@xxxxxxxx > > Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx > > Cc: alexander.deucher@xxxxxxx > > Cc: christian.koenig@xxxxxxx > > --- > > 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 <daniel.vetter@xxxxxxxx> > > > 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 -- Ville Syrjälä Intel OTC _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
