drm/nouveau/disp: check that panel power gpio is enabled at init time

Reported-by: Yuriy Khomchik <homyur@gmail.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nouveau_bios.h

@@ -54,9 +54,10 @@ struct bit_entry {
 int bit_table(struct drm_device *, u8 id, struct bit_entry *);
 
 enum dcb_gpio_tag {
-	DCB_GPIO_TVDAC0 = 0xc,
+	DCB_GPIO_PANEL_POWER = 0x01,
+	DCB_GPIO_TVDAC0 = 0x0c,
 	DCB_GPIO_TVDAC1 = 0x2d,
-	DCB_GPIO_PWM_FAN = 0x9,
+	DCB_GPIO_PWM_FAN = 0x09,
 	DCB_GPIO_FAN_SENSE = 0x3d,
 	DCB_GPIO_UNUSED = 0xff
 };

drivers/gpu/drm/nouveau/nouveau_display.c

@@ -219,6 +219,16 @@ nouveau_display_init(struct drm_device *dev)
 	if (ret)
 		return ret;
 
+	/* power on internal panel if it's not already.  the init tables of
+	 * some vbios default this to off for some reason, causing the
+	 * panel to not work after resume
+	 */
+	if (nouveau_gpio_func_get(dev, DCB_GPIO_PANEL_POWER) == 0) {
+		nouveau_gpio_func_set(dev, DCB_GPIO_PANEL_POWER, true);
+		msleep(300);
+	}
+
+	/* enable polling for external displays */
 	drm_kms_helper_poll_enable(dev);
 
 	/* enable hotplug interrupts */