bcm27xx: add support for linux v5.15

Build system: x86_64
Build-tested: bcm2708, bcm2709, bcm2710, bcm2711
Run-tested: bcm2708/RPiB+, bcm2709/RPi3B, bcm2710/RPi3B, bcm2711/RPi4B

Signed-off-by: Marty Jones <mj8263788@gmail.com>
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>

1 files changed, 34 insertions, 0 deletions

diff --git a/target/linux/bcm27xx/patches-5.15/950-0228-video-bcm2708_fb-Disable-FB-if-no-displays-found.patch b/target/linux/bcm27xx/patches-5.15/950-0228-video-bcm2708_fb-Disable-FB-if-no-displays-found.patch
new file mode 100644
index 0000000000..558340b306
--- /dev/null
+++ b/target/linux/bcm27xx/patches-5.15/950-0228-video-bcm2708_fb-Disable-FB-if-no-displays-found.patch
@@ -0,0 +1,34 @@
+From aef696eeab7a0a8122e9da3021b4310674539bb9 Mon Sep 17 00:00:00 2001
+From: Phil Elwell <phil@raspberrypi.com>
+Date: Tue, 5 May 2020 19:45:41 +0100
+Subject: [PATCH] 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>
+---
+ drivers/video/fbdev/bcm2708_fb.c | 5 ++---
+ 1 file changed, 2 insertions(+), 3 deletions(-)
+
+--- a/drivers/video/fbdev/bcm2708_fb.c
++++ b/drivers/video/fbdev/bcm2708_fb.c
+@@ -1092,10 +1092,9 @@ static int bcm2708_fb_probe(struct platf
+ 	 * 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;
+ 	}