[PATCH 1/6] drm/amdgpu: allow ioctls to opt-out of runtime pm

[Pierre-Eric Pelloux-Prayer]

Waking up a device can take multiple seconds, so if it's not
going to be used we might as well not resume it.

The safest default behavior for all ioctls is to resume the GPU,
so this change allows specific ioctls to opt-out of generic
runtime pm.

Signed-off-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index 60d5758939ae..a9831b243bfc 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -2855,18 +2855,33 @@ long amdgpu_drm_ioctl(struct file *filp,
 {
 	struct drm_file *file_priv = filp->private_data;
 	struct drm_device *dev;
+	bool needs_device;
 	long ret;
 
 	dev = file_priv->minor->dev;
-	ret = pm_runtime_get_sync(dev->dev);
-	if (ret < 0)
-		goto out;
+
+	/* Some ioctl can opt-out of powermanagement handling
+	 * if they don't require the device to be resumed.
+	 */
+	switch (cmd) {
+	default:
+		needs_device = true;
+	}
+
+	if (needs_device) {
+		ret = pm_runtime_get_sync(dev->dev);
+		if (ret < 0)
+			goto out;
+	}
 
 	ret = drm_ioctl(filp, cmd, arg);
 
-	pm_runtime_mark_last_busy(dev->dev);
 out:
-	pm_runtime_put_autosuspend(dev->dev);
+	if (needs_device) {
+		pm_runtime_mark_last_busy(dev->dev);
+		pm_runtime_put_autosuspend(dev->dev);
+	}
+
 	return ret;
 }
 
-- 
2.40.1