target/linux/brcm2708/patches-4.19/950-0597-drm-vc4-Fix-vblank-timestamping-for-firmwarekms.patch

   1 From 3b341544a3dae555d48ece948c44b3b434543077 Mon Sep 17 00:00:00 2001
   2 From: Eric Anholt <eric@anholt.net>
   3 Date: Tue, 2 Apr 2019 13:29:00 -0700
   4 Subject: [PATCH 597/703] drm/vc4: Fix vblank timestamping for firmwarekms.
   5
   6 The core doesn't expect a false return from the scanoutpos function in
   7 normal usage, so we were doing the precise vblank timestamping path
   8 and thus "immediate" vblank disables (even though firmwarekms can't
   9 actually disable vblanks interrupts, sigh), and the kernel would get
  10 confused when getting timestamp info when also turning vblanks back
  11 on.
  12
  13 Signed-off-by: Eric Anholt <eric@anholt.net>
  14 ---
  15  drivers/gpu/drm/vc4/vc4_crtc.c         | 3 ---
  16  drivers/gpu/drm/vc4/vc4_firmware_kms.c | 6 ++++++
  17  2 files changed, 6 insertions(+), 3 deletions(-)
  18
  19 --- a/drivers/gpu/drm/vc4/vc4_crtc.c
  20 +++ b/drivers/gpu/drm/vc4/vc4_crtc.c
  21 @@ -133,9 +133,6 @@ bool vc4_crtc_get_scanoutpos(struct drm_
  22         int vblank_lines;
  23         bool ret = false;
  24
  25 -       if (vc4->firmware_kms)
  26 -               return 0;
  27 -
  28         /* preempt_disable_rt() should go right here in PREEMPT_RT patchset. */
  29
  30         /* Get optional system timestamp before query. */
  31 --- a/drivers/gpu/drm/vc4/vc4_firmware_kms.c
  32 +++ b/drivers/gpu/drm/vc4/vc4_firmware_kms.c
  33 @@ -673,6 +673,12 @@ static int vc4_fkms_bind(struct device *
  34
  35         vc4->firmware_kms = true;
  36
  37 +       /* firmware kms doesn't have precise a scanoutpos implementation, so
  38 +        * we can't do the precise vblank timestamp mode.
  39 +        */
  40 +       drm->driver->get_scanout_position = NULL;
  41 +       drm->driver->get_vblank_timestamp = NULL;
  42 +
  43         vc4_crtc = devm_kzalloc(dev, sizeof(*vc4_crtc), GFP_KERNEL);
  44         if (!vc4_crtc)
  45                 return -ENOMEM;