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. 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 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
