target/linux/bcm27xx/patches-5.4/950-0710-video-bcm2708_fb-Disable-FB-if-no-displays-found.patch

   1 From e005a4db95a48e8b14a2017bf56a0e3f3dccfa6d Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.com>
   3 Date: Tue, 5 May 2020 19:45:41 +0100
   4 Subject: [PATCH] video: bcm2708_fb: Disable FB if no displays found
   5
   6 If the firmware hasn't detected a display, the driver would assume
   7 one display was available, but because it had failed to retrieve the
   8 display size it would try to allocate a zero-sized buffer.
   9
  10 Avoid the allocation failure by bailing out early if no display is
  11 found.
  12
  13 See: https://github.com/raspberrypi/linux/issues/3598
  14
  15 Signed-off-by: Phil Elwell <phil@raspberrypi.com>
  16 ---
  17  drivers/video/fbdev/bcm2708_fb.c | 5 ++---
  18  1 file changed, 2 insertions(+), 3 deletions(-)
  19
  20 --- a/drivers/video/fbdev/bcm2708_fb.c
  21 +++ b/drivers/video/fbdev/bcm2708_fb.c
  22 @@ -1104,10 +1104,9 @@ static int bcm2708_fb_probe(struct platf
  23          * set one display
  24          */
  25         if (ret || num_displays == 0) {
  26 -               num_displays = 1;
  27                 dev_err(&dev->dev,
  28 -                       "Unable to determine number of FB's. Assuming 1\n");
  29 -               ret = 0;
  30 +                       "Unable to determine number of FBs. Disabling driver.\n");
  31 +               return -ENOENT;
  32         } else {
  33                 fbdev->firmware_supports_multifb = 1;
  34         }