[PATCH 2/6] drm/amdgpu: skip runtime pm for selected ioctls

[Pierre-Eric Pelloux-Prayer]

These ioctls don't need to GPU, so don't resume it.

Signed-off-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 45 +++++++++++++++++++++++--
 1 file changed, 42 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index a9831b243bfc..d21d5af7f187 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -2855,7 +2855,9 @@ long amdgpu_drm_ioctl(struct file *filp,
 {
 	struct drm_file *file_priv = filp->private_data;
 	struct drm_device *dev;
+	bool is_driver_ioctl;
 	bool needs_device;
+	unsigned int nr;
 	long ret;
 
 	dev = file_priv->minor->dev;
@@ -2863,9 +2865,46 @@ long amdgpu_drm_ioctl(struct file *filp,
 	/* Some ioctl can opt-out of powermanagement handling
 	 * if they don't require the device to be resumed.
 	 */
-	switch (cmd) {
-	default:
-		needs_device = true;
+	nr = DRM_IOCTL_NR(cmd);
+
+	is_driver_ioctl = nr >= DRM_COMMAND_BASE && nr < DRM_COMMAND_END;
+
+	if (is_driver_ioctl) {
+		switch (nr - DRM_COMMAND_BASE) {
+		/* These 4 only operate on kernel data structure. */
+		case DRM_AMDGPU_VM:
+		case DRM_AMDGPU_SCHED:
+		case DRM_AMDGPU_BO_LIST:
+		case DRM_AMDGPU_FENCE_TO_HANDLE:
+		/* All the waits don't need to resume up the device. If there are
+		 * jobs in progress, the device can't be in suspended state. And if
+		 * there's nothing no in-flight jobs, then the waits are no-op.
+		 */
+		case DRM_AMDGPU_GEM_WAIT_IDLE:
+		case DRM_AMDGPU_WAIT_CS:
+		case DRM_AMDGPU_WAIT_FENCES:
+			needs_device = false;
+			break;
+		default:
+			needs_device = true;
+		}
+	} else {
+		/* Most drm core ioctls don't need the device, but to avoid missing one
+		 * that requires it, implement the "can skip pm" logic as an allow list.
+		 */
+		switch (nr) {
+		case DRM_IOCTL_NR(DRM_IOCTL_VERSION):
+		case DRM_IOCTL_NR(DRM_IOCTL_AUTH_MAGIC):
+		case DRM_IOCTL_NR(DRM_IOCTL_GET_CAP):
+		case DRM_IOCTL_NR(DRM_IOCTL_SYNCOBJ_CREATE):
+		/* Same logic as DRM_AMDGPU_WAIT_* */
+		case DRM_IOCTL_NR(DRM_IOCTL_SYNCOBJ_WAIT):
+		case DRM_IOCTL_NR(DRM_IOCTL_SYNCOBJ_DESTROY):
+			needs_device = false;
+			break;
+		default:
+			needs_device = true;
+		}
 	}
 
 	if (needs_device) {
-- 
2.40.1