target/linux/brcm2708/patches-4.4/0341-drm-vc4-Fix-drm_vblank_put-get-imbalance-in-page-fli.patch

   1 From 4f9f74feec3951986a22aff184d0fa6fb7a47b93 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 341/423] drm/vc4: Fix drm_vblank_put/get imbalance in page
   5  flip path.
   6
   7 The async page flip path was missing drm_crtc_vblank_get/put
   8 completely. The sync flip path was missing a vblank put, so async
   9 flips only reported proper pageflip completion events by chance,
  10 and vblank irq's never turned off after a first vsync'ed page flip
  11 until system reboot.
  12
  13 Tested against Raspian kernel 4.4.8 tree on RPi 2B.
  14
  15 Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
  16 Cc: Eric Anholt <eric@anholt.net>
  17 Signed-off-by: Eric Anholt <eric@anholt.net>
  18 ---
  19  drivers/gpu/drm/vc4/vc4_crtc.c | 4 ++++
  20  1 file changed, 4 insertions(+)
  21
  22 --- a/drivers/gpu/drm/vc4/vc4_crtc.c
  23 +++ b/drivers/gpu/drm/vc4/vc4_crtc.c
  24 @@ -506,6 +506,7 @@ static void vc4_crtc_handle_page_flip(st
  25         if (vc4_crtc->event) {
  26                 drm_crtc_send_vblank_event(crtc, vc4_crtc->event);
  27                 vc4_crtc->event = NULL;
  28 +               drm_crtc_vblank_put(crtc);
  29         }
  30         spin_unlock_irqrestore(&dev->event_lock, flags);
  31  }
  32 @@ -556,6 +557,7 @@ vc4_async_page_flip_complete(struct vc4_
  33                 spin_unlock_irqrestore(&dev->event_lock, flags);
  34         }
  35
  36 +       drm_crtc_vblank_put(crtc);
  37         drm_framebuffer_unreference(flip_state->fb);
  38         kfree(flip_state);
  39
  40 @@ -598,6 +600,8 @@ static int vc4_async_page_flip(struct dr
  41                 return ret;
  42         }
  43
  44 +       WARN_ON(drm_crtc_vblank_get(crtc) != 0);
  45 +
  46         /* Immediately update the plane's legacy fb pointer, so that later
  47          * modeset prep sees the state that will be present when the semaphore
  48          * is released.