From: Marek Vasut <marex@denx.de> stable inclusion from stable-5.10.65 commit b6b5dc12bd7cb70792db0c02dd74392be4189183 bugzilla: 182361 https://gitee.com/openeuler/kernel/issues/I4EH3U Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 5e23c98178eb1a2cdb7c4fee9a39baf8cabf282d ] 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 <marex@denx.de> Cc: Daniel Abrecht <public@danielabrecht.ch> Cc: Emil Velikov <emil.l.velikov@gmail.com> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Cc: Lucas Stach <l.stach@pengutronix.de> Cc: Stefan Agner <stefan@agner.ch> Reviewed-by: Jagan Teki <jagan@amarulasolutions.com> Tested-by: Jagan Teki <jagan@amarulasolutions.com> # i.Core MX8MM Acked-by: Lucas Stach <l.stach@pengutronix.de> Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Link: https://patchwork.freedesktop.org/patch/msgid/20210620224946.189524-1-marex@... Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Chen Jun <chenjun102@huawei.com> Acked-by: Weilong Chen <chenweilong@huawei.com> Signed-off-by: Chen Jun <chenjun102@huawei.com> --- 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 007ea29abfcc..b535621f4f78 100644 --- a/drivers/gpu/drm/mxsfb/mxsfb_kms.c +++ b/drivers/gpu/drm/mxsfb/mxsfb_kms.c @@ -243,6 +243,9 @@ 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); -- 2.20.1