target/linux/brcm2708/patches-4.4/0340-drm-vc4-Fix-drm_vblank_put-get-imbalance-in-page-fli.patch

   1 From bd3aef6d9474fbb9fe063a2f409f920263c28ff1 Mon Sep 17 00:00:00 2001
   2 From: Mario Kleiner <mario.kleiner.de@gmail.com>
   3 Date: Fri, 6 May 2016 19:26:06 +0200
   4 Subject: [PATCH] drm/vc4: Fix drm_vblank_put/get imbalance in page flip path.
   5
   6 The async page flip path was missing drm_crtc_vblank_get/put
   7 completely. The sync flip path was missing a vblank put, so async
   8 flips only reported proper pageflip completion events by chance,
   9 and vblank irq's never turned off after a first vsync'ed page flip
  10 until system reboot.
  11
  12 Tested against Raspian kernel 4.4.8 tree on RPi 2B.
  13
  14 Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
  15 Cc: Eric Anholt <eric@anholt.net>
  16 Signed-off-by: Eric Anholt <eric@anholt.net>
  17 ---
  18  drivers/gpu/drm/vc4/vc4_crtc.c | 4 ++++
  19  1 file changed, 4 insertions(+)
  20
  21 --- a/drivers/gpu/drm/vc4/vc4_crtc.c
  22 +++ b/drivers/gpu/drm/vc4/vc4_crtc.c
  23 @@ -506,6 +506,7 @@ static void vc4_crtc_handle_page_flip(st
  24         if (vc4_crtc->event) {
  25                 drm_crtc_send_vblank_event(crtc, vc4_crtc->event);
  26                 vc4_crtc->event = NULL;
  27 +               drm_crtc_vblank_put(crtc);
  28         }
  29         spin_unlock_irqrestore(&dev->event_lock, flags);
  30  }
  31 @@ -556,6 +557,7 @@ vc4_async_page_flip_complete(struct vc4_
  32                 spin_unlock_irqrestore(&dev->event_lock, flags);
  33         }
  34
  35 +       drm_crtc_vblank_put(crtc);
  36         drm_framebuffer_unreference(flip_state->fb);
  37         kfree(flip_state);
  38
  39 @@ -598,6 +600,8 @@ static int vc4_async_page_flip(struct dr
  40                 return ret;
  41         }
  42
  43 +       WARN_ON(drm_crtc_vblank_get(crtc) != 0);
  44 +
  45         /* Immediately update the plane's legacy fb pointer, so that later
  46          * modeset prep sees the state that will be present when the semaphore
  47          * is released.