Make sure the FIFO_CLEAR bit is latched in when configuring the
controller, so that the FIFO is really cleared. And then clear
the FIFO_CLEAR bit, since it is not self-clearing.
Fixes: 45d59d704080 ("drm: Add new driver for MXSFB controller")
Signed-off-by: Marek Vasut <ma...@denx.de>
Cc: Daniel Abrecht <pub...@danielabrecht.ch>
Cc: Emil Velikov <emil.l.veli...@gmail.com>
Cc: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
Cc: Lucas Stach <l.st...@pengutronix.de>
Cc: Stefan Agner <ste...@agner.ch>
---
drivers/gpu/drm/mxsfb/mxsfb_kms.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/gpu/drm/mxsfb/mxsfb_kms.c
b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
index 98d8ba0bae84..22cb749fc9bc 100644
--- a/drivers/gpu/drm/mxsfb/mxsfb_kms.c
+++ b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
@@ -241,6 +241,9 @@ static void mxsfb_crtc_mode_set_nofb(struct
mxsfb_drm_private *mxsfb,
/* Clear the FIFOs */
writel(CTRL1_FIFO_CLEAR, mxsfb->base + LCDC_CTRL1 + REG_SET);
+ readl(mxsfb->base + LCDC_CTRL1);
+ writel(CTRL1_FIFO_CLEAR, mxsfb->base + LCDC_CTRL1 + REG_CLR);
+ readl(mxsfb->base + LCDC_CTRL1);
if (mxsfb->devdata->has_overlay)
writel(0, mxsfb->base + LCDC_AS_CTRL);
--
2.30.2
