target/linux/brcm2708/patches-4.4/0518-drm-vc4-Enable-precise-vblank-timestamping-for-inter.patch

   1 From f2494f314f8c71e41ddd6798315685ecb6fc7814 Mon Sep 17 00:00:00 2001
   2 From: Mario Kleiner <mario.kleiner.de@gmail.com>
   3 Date: Tue, 19 Jul 2016 20:59:00 +0200
   4 Subject: [PATCH] drm/vc4: Enable precise vblank timestamping for interlaced
   5  modes.
   6
   7 On top of the interlaced video mode fix and with some additional
   8 adjustments, this now works well. It has almost the same accuracy
   9 as on regular progressive scan modes.
  10
  11 Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
  12 Signed-off-by: Eric Anholt <eric@anholt.net>
  13 ---
  14  drivers/gpu/drm/vc4/vc4_crtc.c | 21 ++++++++-------------
  15  1 file changed, 8 insertions(+), 13 deletions(-)
  16
  17 --- a/drivers/gpu/drm/vc4/vc4_crtc.c
  18 +++ b/drivers/gpu/drm/vc4/vc4_crtc.c
  19 @@ -154,14 +154,6 @@ int vc4_crtc_get_scanoutpos(struct drm_d
  20         if (vc4->firmware_kms)
  21                 return 0;
  22
  23 -       /*
  24 -        * XXX Doesn't work well in interlaced mode yet, partially due
  25 -        * to problems in vc4 kms or drm core interlaced mode handling,
  26 -        * so disable for now in interlaced mode.
  27 -        */
  28 -       if (mode->flags & DRM_MODE_FLAG_INTERLACE)
  29 -               return ret;
  30 -
  31         /* preempt_disable_rt() should go right here in PREEMPT_RT patchset. */
  32
  33         /* Get optional system timestamp before query. */
  34 @@ -182,10 +174,15 @@ int vc4_crtc_get_scanoutpos(struct drm_d
  35
  36         /* Vertical position of hvs composed scanline. */
  37         *vpos = VC4_GET_FIELD(val, SCALER_DISPSTATX_LINE);
  38 +       *hpos = 0;
  39 +
  40 +       if (mode->flags & DRM_MODE_FLAG_INTERLACE) {
  41 +               *vpos /= 2;
  42
  43 -       /* No hpos info available. */
  44 -       if (hpos)
  45 -               *hpos = 0;
  46 +               /* Use hpos to correct for field offset in interlaced mode. */
  47 +               if (VC4_GET_FIELD(val, SCALER_DISPSTATX_FRAME_COUNT) % 2)
  48 +                       *hpos += mode->crtc_htotal / 2;
  49 +       }
  50
  51         /* This is the offset we need for translating hvs -> pv scanout pos. */
  52         fifo_lines = vc4_crtc->cob_size / mode->crtc_hdisplay;
  53 @@ -208,8 +205,6 @@ int vc4_crtc_get_scanoutpos(struct drm_d
  54                  * position of the PV.
  55                  */
  56                 *vpos -= fifo_lines + 1;
  57 -               if (mode->flags & DRM_MODE_FLAG_INTERLACE)
  58 -                       *vpos /= 2;
  59
  60                 ret |= DRM_SCANOUTPOS_ACCURATE;
  61                 return ret;