Messages in this thread | | | From | Dave Stevenson <> | Date | Wed, 29 Jul 2020 15:09:21 +0100 | Subject | Re: [PATCH v4 29/78] drm/vc4: crtc: Add a delay after disabling the PixelValve output |
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Hi Maxime
On Wed, 8 Jul 2020 at 18:43, Maxime Ripard <maxime@cerno.tech> wrote: > > In order to avoid pixels getting stuck in the (unflushable) FIFO between > the HVS and the PV, we need to add some delay after disabling the PV output > and before disabling the HDMI controller. 20ms seems to be good enough so > let's use that. > > Signed-off-by: Maxime Ripard <maxime@cerno.tech> > --- > drivers/gpu/drm/vc4/vc4_crtc.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/gpu/drm/vc4/vc4_crtc.c b/drivers/gpu/drm/vc4/vc4_crtc.c > index d0b326e1df0a..7b178d67187f 100644 > --- a/drivers/gpu/drm/vc4/vc4_crtc.c > +++ b/drivers/gpu/drm/vc4/vc4_crtc.c > @@ -403,6 +403,8 @@ static void vc4_crtc_atomic_disable(struct drm_crtc *crtc, > ret = wait_for(!(CRTC_READ(PV_V_CONTROL) & PV_VCONTROL_VIDEN), 1); > WARN_ONCE(ret, "Timeout waiting for !PV_VCONTROL_VIDEN\n"); > > + mdelay(20);
mdelay for 20ms seems a touch unfriendly as it's a busy wait. Can we not msleep instead?
Dave
> + > if (vc4_encoder->post_crtc_disable) > vc4_encoder->post_crtc_disable(encoder); > > -- > git-series 0.9.1
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