On 02/09/2016 12:10 PM, Ville Syrjälä 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 <mario.kleiner.de at gmail.com> >>> Cc: <stable at vger.kernel.org> # 3.18+ >>> Cc: michel at daenzer.net >>> Cc: vbabka at suse.cz >>> Cc: ville.syrjala at linux.intel.com >>> Cc: daniel.vetter at ffwll.ch >>> Cc: dri-devel at lists.freedesktop.org >>> Cc: alexander.deucher at amd.com >>> Cc: christian.koenig at 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 <daniel.vetter at ffwll.ch> >>
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 >
