[PATCH 08/12] drm/sun4i: sun6i_mipi_dsi: Refactor vertical video start delay
From: jagan@amarulasolutions.com (Jagan Teki)
Date: 2018-09-27 11:50:14
Also in:
dri-devel, linux-clk, linux-devicetree, lkml
Subsystem:
drm drivers, drm drivers and misc gpu patches, drm drivers for allwinner a10, the rest · Maintainers:
David Airlie, Simona Vetter, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, Chen-Yu Tsai, Linus Torvalds
Accordingly to BPI-M64-bsp DE DSI code Video start delay can be computed by subtracting total vertical timing with front porch timing and with adding 1 delay line for TCON. This patch simply add the start_delay logic from BPI-M64-bsp, w/o this new computation, the DSI on A64 encounter vblank time out. [CRTC:36:crtc-0] vblank wait timed out Signed-off-by: Jagan Teki <jagan@amarulasolutions.com> --- drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
index 9918fdb990ff..217db74c6dc3 100644
--- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
+++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c@@ -358,7 +358,17 @@ static void sun6i_dsi_inst_init(struct sun6i_dsi *dsi, static u16 sun6i_dsi_get_video_start_delay(struct sun6i_dsi *dsi, struct drm_display_mode *mode) { - return mode->vtotal - (mode->vsync_end - mode->vdisplay) + 1; + u32 vfp = mode->vsync_start - mode->vdisplay; + u32 start_delay; + + start_delay = mode->vtotal - vfp + 1; + if (start_delay > mode->vtotal) + start_delay -= mode->vtotal; + + if (!start_delay) + start_delay = 1; + + return start_delay; } static void sun6i_dsi_setup_burst(struct sun6i_dsi *dsi,
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2.18.0.321.gffc6fa0e3