From mboxrd@z Thu Jan  1 00:00:00 1970
From: Peng Fan <van.freenix@gmail.com>
Date: Wed, 22 Feb 2017 17:58:55 +0800
Subject: [U-Boot] [PATCH] video: mxsfb: Fix reset hang when videomode
 variable is not present
In-Reply-To: <1487757144-11823-1-git-send-email-festevam@gmail.com>
References: <1487757144-11823-1-git-send-email-festevam@gmail.com>
Message-ID: <20170222095853.GB9692@linux-7smt.suse>
List-Id: <u-boot.lists.denx.de>
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To: u-boot@lists.denx.de

Hi Fabio,

On Wed, Feb 22, 2017 at 06:52:24AM -0300, Fabio Estevam wrote:
>From: Fabio Estevam <fabio.estevam@nxp.com>
>
>Currently the system hangs when the 'videomode' variable is not present:
>
>=> setenv videomode
>=> saveenv
>=> reset
>
>(Board hangs)
>
>lcdif_power_down() assumes that the LCDIF controller has been properly
>configured and enabled, which may not be true.
>
>To fix this issue check whether video_hw_init() succeeded or not and only
>perform the LCDIF shutdown when the controller has been properly enabled.
>
>Tested on a imx7dsabresd board.
>
>Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
>---
> drivers/video/mxsfb.c | 3 +++
> 1 file changed, 3 insertions(+)
>
>diff --git a/drivers/video/mxsfb.c b/drivers/video/mxsfb.c
>index 3cc03ca..83fd9aa 100644
>--- a/drivers/video/mxsfb.c
>+++ b/drivers/video/mxsfb.c
>@@ -136,6 +136,9 @@ void lcdif_power_down(void)
> 	struct mxs_lcdif_regs *regs = (struct mxs_lcdif_regs *)MXS_LCDIF_BASE;
> 	int timeout = 1000000;
> 
>+	if (!video_hw_init())
>+		return;

If videomode is set, this will reinitialize the lcdif.
Checking videomode env is ok to handle it as you proposed just now.

Regards,
Peng.