drm/nouveau/kms/nv50-: wait for FIFO space on PIO channels

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/dispnv50/curs507a.c

@@ -24,21 +24,36 @@
 #include "head.h"
 
 #include <nvif/cl507a.h>
+#include <nvif/timer.h>
 
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_plane_helper.h>
 
+bool
+curs507a_space(struct nv50_wndw *wndw)
+{
+	nvif_msec(&nouveau_drm(wndw->plane.dev)->client.device, 2,
+		if (nvif_rd32(&wndw->wimm.base.user, 0x0008) >= 4)
+			return true;
+	);
+	WARN_ON(1);
+	return false;
+}
+
 static void
 curs507a_update(struct nv50_wndw *wndw, u32 *interlock)
 {
+	if (curs507a_space(wndw))
 		nvif_wr32(&wndw->wimm.base.user, 0x0080, 0x00000000);
 }
 
 static void
 curs507a_point(struct nv50_wndw *wndw, struct nv50_wndw_atom *asyw)
 {
+	if (curs507a_space(wndw)) {
 		nvif_wr32(&wndw->wimm.base.user, 0x0084, asyw->point.y << 16 |
 							 asyw->point.x);
+	}
 }
 
 const struct nv50_wimm_func

drivers/gpu/drm/nouveau/dispnv50/cursc37a.c

@@ -25,14 +25,17 @@
 static void
 cursc37a_update(struct nv50_wndw *wndw, u32 *interlock)
 {
+	if (curs507a_space(wndw))
 		nvif_wr32(&wndw->wimm.base.user, 0x0200, 0x00000001);
 }
 
 static void
 cursc37a_point(struct nv50_wndw *wndw, struct nv50_wndw_atom *asyw)
 {
+	if (curs507a_space(wndw)) {
 		nvif_wr32(&wndw->wimm.base.user, 0x0208, asyw->point.y << 16 |
 							 asyw->point.x);
+	}
 }
 
 static const struct nv50_wimm_func

drivers/gpu/drm/nouveau/dispnv50/wndw.h

@@ -97,6 +97,7 @@ struct nv50_wimm_func {
 };
 
 extern const struct nv50_wimm_func curs507a;
+bool curs507a_space(struct nv50_wndw *);
 
 int wndwc37e_new(struct nouveau_drm *, enum drm_plane_type, int, s32,
 		 struct nv50_wndw **);