From 7d4283ff6db6bc25f3a018d958d09d5bc49a85bd Mon Sep 17 00:00:00 2001 From: Eric Anholt Date: Fri, 4 Nov 2016 15:58:38 -0700 Subject: [PATCH] drm/vc4: Use runtime autosuspend to avoid thrashing V3D power state. The pm_runtime_put() we were using immediately released power on the device, which meant that we were generally turning the device off and on once per frame. In many profiles I've looked at, that added up to about 1% of CPU time, but this could get worse in the case of frequent rendering and readback (as may happen in X rendering). By keeping the device on until we've been idle for a couple of frames, we drop the overhead of runtime PM down to sub-.1%. Signed-off-by: Eric Anholt --- drivers/gpu/drm/vc4/vc4_drv.c | 9 ++++++--- drivers/gpu/drm/vc4/vc4_gem.c | 6 ++++-- drivers/gpu/drm/vc4/vc4_v3d.c | 2 ++ 3 files changed, 12 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c index b087404c2784b..7abfe088f2d10 100644 --- a/drivers/gpu/drm/vc4/vc4_drv.c +++ b/drivers/gpu/drm/vc4/vc4_drv.c @@ -61,21 +61,24 @@ static int vc4_get_param_ioctl(struct drm_device *dev, void *data, if (ret < 0) return ret; args->value = V3D_READ(V3D_IDENT0); - pm_runtime_put(&vc4->v3d->pdev->dev); + pm_runtime_mark_last_busy(&vc4->v3d->pdev->dev); + pm_runtime_put_autosuspend(&vc4->v3d->pdev->dev); break; case DRM_VC4_PARAM_V3D_IDENT1: ret = pm_runtime_get_sync(&vc4->v3d->pdev->dev); if (ret < 0) return ret; args->value = V3D_READ(V3D_IDENT1); - pm_runtime_put(&vc4->v3d->pdev->dev); + pm_runtime_mark_last_busy(&vc4->v3d->pdev->dev); + pm_runtime_put_autosuspend(&vc4->v3d->pdev->dev); break; case DRM_VC4_PARAM_V3D_IDENT2: ret = pm_runtime_get_sync(&vc4->v3d->pdev->dev); if (ret < 0) return ret; args->value = V3D_READ(V3D_IDENT2); - pm_runtime_put(&vc4->v3d->pdev->dev); + pm_runtime_mark_last_busy(&vc4->v3d->pdev->dev); + pm_runtime_put_autosuspend(&vc4->v3d->pdev->dev); break; case DRM_VC4_PARAM_SUPPORTS_BRANCHES: case DRM_VC4_PARAM_SUPPORTS_ETC1: diff --git a/drivers/gpu/drm/vc4/vc4_gem.c b/drivers/gpu/drm/vc4/vc4_gem.c index 303f23c962206..db920771bfb56 100644 --- a/drivers/gpu/drm/vc4/vc4_gem.c +++ b/drivers/gpu/drm/vc4/vc4_gem.c @@ -709,8 +709,10 @@ vc4_complete_exec(struct drm_device *dev, struct vc4_exec_info *exec) } mutex_lock(&vc4->power_lock); - if (--vc4->power_refcount == 0) - pm_runtime_put(&vc4->v3d->pdev->dev); + if (--vc4->power_refcount == 0) { + pm_runtime_mark_last_busy(&vc4->v3d->pdev->dev); + pm_runtime_put_autosuspend(&vc4->v3d->pdev->dev); + } mutex_unlock(&vc4->power_lock); kfree(exec); diff --git a/drivers/gpu/drm/vc4/vc4_v3d.c b/drivers/gpu/drm/vc4/vc4_v3d.c index e6d3c6028341e..7cc346ad9b0ba 100644 --- a/drivers/gpu/drm/vc4/vc4_v3d.c +++ b/drivers/gpu/drm/vc4/vc4_v3d.c @@ -222,6 +222,8 @@ static int vc4_v3d_bind(struct device *dev, struct device *master, void *data) return ret; } + pm_runtime_use_autosuspend(dev); + pm_runtime_set_autosuspend_delay(dev, 40); /* a little over 2 frames. */ pm_runtime_enable(dev); return 0; -- 2.39.5