[PATCH v4 29/78] drm/vc4: crtc: Add a delay after disabling the PixelValve output
From: Maxime Ripard <hidden>
Date: 2020-07-08 17:43:19
Also in:
dri-devel, lkml
Subsystem:
drm drivers, drm drivers and misc gpu patches, drm drivers for vc4, the rest · Maintainers:
David Airlie, Simona Vetter, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, Dave Stevenson, Linus Torvalds
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 <redacted> --- 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); + if (vc4_encoder->post_crtc_disable) vc4_encoder->post_crtc_disable(encoder);
--
git-series 0.9.1
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