From: Phil Elwell <phil@raspberrypi.com>
Date: Tue, 5 May 2020 18:45:41 +0000 (+0100)
Subject: video: bcm2708_fb: Disable FB if no displays found
X-Git-Tag: accepted/tizen/unified/20230118.172025~1341
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=6377fe384a32432c5b9c42e54e4fa72c946501c9;p=platform%2Fkernel%2Flinux-rpi.git

video: bcm2708_fb: Disable FB if no displays found

If the firmware hasn't detected a display, the driver would assume
one display was available, but because it had failed to retrieve the
display size it would try to allocate a zero-sized buffer.

Avoid the allocation failure by bailing out early if no display is
found.

See: https://github.com/raspberrypi/linux/issues/3598

Signed-off-by: Phil Elwell <phil@raspberrypi.com>
---

diff --git a/drivers/video/fbdev/bcm2708_fb.c b/drivers/video/fbdev/bcm2708_fb.c
index 17e9260..dac5c02 100644
--- a/drivers/video/fbdev/bcm2708_fb.c
+++ b/drivers/video/fbdev/bcm2708_fb.c
@@ -1092,10 +1092,9 @@ static int bcm2708_fb_probe(struct platform_device *dev)
 	 * set one display
 	 */
 	if (ret || num_displays == 0) {
-		num_displays = 1;
 		dev_err(&dev->dev,
-			"Unable to determine number of FB's. Assuming 1\n");
-		ret = 0;
+			"Unable to determine number of FBs. Disabling driver.\n");
+		return -ENOENT;
 	} else {
 		fbdev->firmware_supports_multifb = 1;
 	}