[PATCH v6 4/5] drm/nouveau/kms: Only allow enabling atomic modesetting on nv50+

[Lyude Paul <lyude@redhat.com>]

Atomic modesetting support was never added for pre-nv50 chipsets, so make
sure we don't allow it to be forced on. Additionally, print a small warning
when it's not supported.

Signed-off-by: Lyude Paul <lyude@redhat.com>

---
V2:
* Check against info.family, not info.chipset
V6:
* Check against device->card_type so we can perform the check before
  setting up nvif

 drivers/gpu/drm/nouveau/nouveau_drm.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c
index d021a3049be1a..82a8061e6d3e2 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_drm.c
@@ -739,10 +739,17 @@ nouveau_drm_device_new(struct device *parent, struct nvkm_device *device)
 	struct nouveau_drm *drm;
 	int ret;
 
-	if (nouveau_atomic)
-		driver = &driver_atomic_kms;
-	else
+	if (device->card_type >= NV_50) {
+		if (nouveau_atomic)
+			driver = &driver_atomic_kms;
+		else
+			driver = &driver_legacy_kms;
+	} else {
+		if (nouveau_atomic)
+			dev_warn(parent, "Atomic modesetting not supported (needs nv50+)\n");
+
 		driver = &driver_legacy_kms;
+	}
 
 	drm = kzalloc_obj(*drm);
 	if (!drm)
-- 
2.55.0