target/linux/bcm27xx/patches-5.4/950-0232-drm-vc4-Fix-vblank-timestamping-for-firmwarekms.patch

   1 From c71f09dafd82a37a488029f33552a45a99d0a9a6 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] 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 | 7 +++++++
  17  2 files changed, 7 insertions(+), 3 deletions(-)
  18
  19 --- a/drivers/gpu/drm/vc4/vc4_crtc.c
  20 +++ b/drivers/gpu/drm/vc4/vc4_crtc.c
  21 @@ -97,9 +97,6 @@ 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 @@ -20,6 +20,7 @@
  34  #include "drm/drm_crtc_helper.h"
  35  #include "drm/drm_fourcc.h"
  36  #include "drm/drm_probe_helper.h"
  37 +#include "drm/drm_drv.h"
  38  #include "linux/clk.h"
  39  #include "linux/debugfs.h"
  40  #include "drm/drm_fb_cma_helper.h"
  41 @@ -673,6 +674,12 @@ static int vc4_fkms_bind(struct device *
  42
  43         vc4->firmware_kms = true;
  44
  45 +       /* firmware kms doesn't have precise a scanoutpos implementation, so
  46 +        * we can't do the precise vblank timestamp mode.
  47 +        */
  48 +       drm->driver->get_scanout_position = NULL;
  49 +       drm->driver->get_vblank_timestamp = NULL;
  50 +
  51         vc4_crtc = devm_kzalloc(dev, sizeof(*vc4_crtc), GFP_KERNEL);
  52         if (!vc4_crtc)
  53                 return -ENOMEM;