Re: [Intel-gfx] [RESEND PATCH v14 2/2] drm/i915: Put "cooked" vlank counters in frame CRC lines

From: Daniel Vetter
Date: Tue Jan 10 2017 - 11:32:00 EST


On Tue, Jan 10, 2017 at 05:54:57PM +0200, Ville Syrjälä wrote:
> On Tue, Jan 10, 2017 at 02:43:05PM +0100, Tomeu Vizoso wrote:
> > Use drm_accurate_vblank_count so we have the full 32 bit to represent
> > the frame counter and userspace has a simpler way of knowing when the
> > counter wraps around.
> >
> > Signed-off-by: Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx>
> > Reviewed-by: Emil Velikov <emil.velikov@xxxxxxxxxxxxx>
> > Reviewed-by: Robert Foss <robert.foss@xxxxxxxxxxxxx>
> > ---
> >
> > drivers/gpu/drm/i915/i915_irq.c | 6 +++---
> > 1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> > index b9beb5955dae..75fb1f66cc0c 100644
> > --- a/drivers/gpu/drm/i915/i915_irq.c
> > +++ b/drivers/gpu/drm/i915/i915_irq.c
> > @@ -1557,7 +1557,6 @@ static void display_pipe_crc_irq_handler(struct drm_i915_private *dev_priv,
> > struct drm_driver *driver = dev_priv->drm.driver;
> > uint32_t crcs[5];
> > int head, tail;
> > - u32 frame;
> >
> > spin_lock(&pipe_crc->lock);
> > if (pipe_crc->source) {
> > @@ -1612,8 +1611,9 @@ static void display_pipe_crc_irq_handler(struct drm_i915_private *dev_priv,
> > crcs[2] = crc2;
> > crcs[3] = crc3;
> > crcs[4] = crc4;
> > - frame = driver->get_vblank_counter(&dev_priv->drm, pipe);
> > - drm_crtc_add_crc_entry(&crtc->base, true, frame, crcs);
> > + drm_crtc_add_crc_entry(&crtc->base, true,
> > + drm_accurate_vblank_count(&crtc->base),
>
> My assumption would be that this gets called after the vblank irq
> handler, so using the _accurate version seems a bit overkill.

Since we're at like v15 of this I figured I'll pull this in, and we can
polish this a bit more later. Tomeu, can you pls do that follow-up patch
and get Ville to review+merge it.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch