target/linux/bcm27xx/patches-4.19/950-0633-Fixup-FKMS-interrupt-handing-for-non-existent-displa.patch

   1 From c2957d7709a43c81e5345d537feaa6980ffcc1a4 Mon Sep 17 00:00:00 2001
   2 From: James Hughes <james.hughes@raspberrypi.org>
   3 Date: Mon, 29 Jul 2019 12:02:59 +0100
   4 Subject: [PATCH] Fixup FKMS interrupt handing for non-existent display
   5
   6 If an errant interrupt flag was received from a non-existent display,
   7 a NULL pointer access was made. Protect against this by checking if a
   8 second display is present prior to checking the interrupt flags.
   9 ---
  10  drivers/gpu/drm/vc4/vc4_firmware_kms.c | 17 ++++++++++-------
  11  1 file changed, 10 insertions(+), 7 deletions(-)
  12
  13 --- a/drivers/gpu/drm/vc4/vc4_firmware_kms.c
  14 +++ b/drivers/gpu/drm/vc4/vc4_firmware_kms.c
  15 @@ -1056,14 +1056,17 @@ static irqreturn_t vc4_crtc_irq_handler(
  16                                 vc4_crtc_handle_page_flip(crtc_list[0]);
  17                         }
  18
  19 -                       /* Check for the secondary display too */
  20 -                       chan = readl(crtc_list[0]->regs + SMIDSW1);
  21 +                       if (crtc_list[1]) {
  22 +                               /* Check for the secondary display too */
  23 +                               chan = readl(crtc_list[0]->regs + SMIDSW1);
  24
  25 -                       if (chan & 1) {
  26 -                               writel(SMI_NEW, crtc_list[0]->regs + SMIDSW1);
  27 -                               if (crtc_list[1]->vblank_enabled)
  28 -                                       drm_crtc_handle_vblank(&crtc_list[1]->base);
  29 -                               vc4_crtc_handle_page_flip(crtc_list[1]);
  30 +                               if (chan & 1) {
  31 +                                       writel(SMI_NEW, crtc_list[0]->regs + SMIDSW1);
  32 +
  33 +                                       if (crtc_list[1]->vblank_enabled)
  34 +                                               drm_crtc_handle_vblank(&crtc_list[1]->base);
  35 +                                       vc4_crtc_handle_page_flip(crtc_list[1]);
  36 +                               }
  37                         }
  38                 }
  39