target/linux/brcm2708/patches-4.9/0164-drm-vc4-Use-runtime-autosuspend-to-avoid-thrashing-V.patch

   1 From 936dc8b00ccd5072c5d610b97199402275bfdf26 Mon Sep 17 00:00:00 2001
   2 From: Eric Anholt <eric@anholt.net>
   3 Date: Fri, 4 Nov 2016 15:58:38 -0700
   4 Subject: [PATCH] drm/vc4: Use runtime autosuspend to avoid thrashing V3D power
   5  state.
   6
   7 The pm_runtime_put() we were using immediately released power on the
   8 device, which meant that we were generally turning the device off and
   9 on once per frame.  In many profiles I've looked at, that added up to
  10 about 1% of CPU time, but this could get worse in the case of frequent
  11 rendering and readback (as may happen in X rendering).  By keeping the
  12 device on until we've been idle for a couple of frames, we drop the
  13 overhead of runtime PM down to sub-.1%.
  14
  15 Signed-off-by: Eric Anholt <eric@anholt.net>
  16 (cherry picked from commit 3a62234680d86efa0239665ed8a0e908f1aef147)
  17 ---
  18  drivers/gpu/drm/vc4/vc4_drv.c | 9 ++++++---
  19  drivers/gpu/drm/vc4/vc4_gem.c | 6 ++++--
  20  drivers/gpu/drm/vc4/vc4_v3d.c | 2 ++
  21  3 files changed, 12 insertions(+), 5 deletions(-)
  22
  23 --- a/drivers/gpu/drm/vc4/vc4_drv.c
  24 +++ b/drivers/gpu/drm/vc4/vc4_drv.c
  25 @@ -61,21 +61,24 @@ static int vc4_get_param_ioctl(struct dr
  26                 if (ret < 0)
  27                         return ret;
  28                 args->value = V3D_READ(V3D_IDENT0);
  29 -               pm_runtime_put(&vc4->v3d->pdev->dev);
  30 +               pm_runtime_mark_last_busy(&vc4->v3d->pdev->dev);
  31 +               pm_runtime_put_autosuspend(&vc4->v3d->pdev->dev);
  32                 break;
  33         case DRM_VC4_PARAM_V3D_IDENT1:
  34                 ret = pm_runtime_get_sync(&vc4->v3d->pdev->dev);
  35                 if (ret < 0)
  36                         return ret;
  37                 args->value = V3D_READ(V3D_IDENT1);
  38 -               pm_runtime_put(&vc4->v3d->pdev->dev);
  39 +               pm_runtime_mark_last_busy(&vc4->v3d->pdev->dev);
  40 +               pm_runtime_put_autosuspend(&vc4->v3d->pdev->dev);
  41                 break;
  42         case DRM_VC4_PARAM_V3D_IDENT2:
  43                 ret = pm_runtime_get_sync(&vc4->v3d->pdev->dev);
  44                 if (ret < 0)
  45                         return ret;
  46                 args->value = V3D_READ(V3D_IDENT2);
  47 -               pm_runtime_put(&vc4->v3d->pdev->dev);
  48 +               pm_runtime_mark_last_busy(&vc4->v3d->pdev->dev);
  49 +               pm_runtime_put_autosuspend(&vc4->v3d->pdev->dev);
  50                 break;
  51         case DRM_VC4_PARAM_SUPPORTS_BRANCHES:
  52         case DRM_VC4_PARAM_SUPPORTS_ETC1:
  53 --- a/drivers/gpu/drm/vc4/vc4_gem.c
  54 +++ b/drivers/gpu/drm/vc4/vc4_gem.c
  55 @@ -711,8 +711,10 @@ vc4_complete_exec(struct drm_device *dev
  56         }
  57
  58         mutex_lock(&vc4->power_lock);
  59 -       if (--vc4->power_refcount == 0)
  60 -               pm_runtime_put(&vc4->v3d->pdev->dev);
  61 +       if (--vc4->power_refcount == 0) {
  62 +               pm_runtime_mark_last_busy(&vc4->v3d->pdev->dev);
  63 +               pm_runtime_put_autosuspend(&vc4->v3d->pdev->dev);
  64 +       }
  65         mutex_unlock(&vc4->power_lock);
  66
  67         kfree(exec);
  68 --- a/drivers/gpu/drm/vc4/vc4_v3d.c
  69 +++ b/drivers/gpu/drm/vc4/vc4_v3d.c
  70 @@ -222,6 +222,8 @@ static int vc4_v3d_bind(struct device *d
  71                 return ret;
  72         }
  73
  74 +       pm_runtime_use_autosuspend(dev);
  75 +       pm_runtime_set_autosuspend_delay(dev, 40); /* a little over 2 frames. */
  76         pm_runtime_enable(dev);
  77
  78         return 0;