drm/nouveau/ppwr: enable ppwr on gm107

For some reason, it is now required to wait a 20 µs after the 0x200 reset of
the engine.
Signed-off-by: Martin Peres <martin.peres@free.fr>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/core/engine/device/gm100.c

@@ -75,8 +75,9 @@ gm100_identify(struct nouveau_device *device)
 		device->oclass[NVDEV_SUBDEV_INSTMEM] =  nv50_instmem_oclass;
 		device->oclass[NVDEV_SUBDEV_VM     ] = &nvc0_vmmgr_oclass;
 		device->oclass[NVDEV_SUBDEV_BAR    ] = &nvc0_bar_oclass;
-#if 0
 		device->oclass[NVDEV_SUBDEV_PWR    ] =  nv108_pwr_oclass;
+
+#if 0
 		device->oclass[NVDEV_SUBDEV_VOLT   ] = &nv40_volt_oclass;
 #endif
 		device->oclass[NVDEV_ENGINE_DMAOBJ ] =  nvd0_dmaeng_oclass;

drivers/gpu/drm/nouveau/core/subdev/pwr/base.c

@@ -204,6 +204,9 @@ _nouveau_pwr_init(struct nouveau_object *object)
 	nv_mask(ppwr, 0x000200, 0x00002000, 0x00000000);
 	nv_mask(ppwr, 0x000200, 0x00002000, 0x00002000);
 
+	/* At least one GM107 needs this delay after reset */
+	udelay(20);
+
 	/* upload data segment */
 	nv_wr32(ppwr, 0x10a1c0, 0x01000000);
 	for (i = 0; i < impl->data.size / 4; i++)