drm/i2c/ch7006: Don't use POWER_LEVEL_FULL_POWER_OFF on early chip versions.

Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
diff --git a/drivers/gpu/drm/i2c/ch7006_drv.c b/drivers/gpu/drm/i2c/ch7006_drv.c
index 833b35f..08792a7 100644
--- a/drivers/gpu/drm/i2c/ch7006_drv.c
+++ b/drivers/gpu/drm/i2c/ch7006_drv.c
@@ -470,6 +470,7 @@
 	priv->hmargin = 50;
 	priv->vmargin = 50;
 	priv->last_dpms = -1;
+	priv->chip_version = ch7006_read(client, CH7006_VERSION_ID);
 
 	if (ch7006_tv_norm) {
 		for (i = 0; i < NUM_TV_NORMS; i++) {
diff --git a/drivers/gpu/drm/i2c/ch7006_mode.c b/drivers/gpu/drm/i2c/ch7006_mode.c
index e447dfb..c860f24 100644
--- a/drivers/gpu/drm/i2c/ch7006_mode.c
+++ b/drivers/gpu/drm/i2c/ch7006_mode.c
@@ -316,7 +316,10 @@
 		}
 
 	} else {
-		*power |= bitfs(CH7006_POWER_LEVEL, FULL_POWER_OFF);
+		if (priv->chip_version >= 0x20)
+			*power |= bitfs(CH7006_POWER_LEVEL, FULL_POWER_OFF);
+		else
+			*power |= bitfs(CH7006_POWER_LEVEL, POWER_OFF);
 	}
 }
 
diff --git a/drivers/gpu/drm/i2c/ch7006_priv.h b/drivers/gpu/drm/i2c/ch7006_priv.h
index 1c6d2e3..17667b7 100644
--- a/drivers/gpu/drm/i2c/ch7006_priv.h
+++ b/drivers/gpu/drm/i2c/ch7006_priv.h
@@ -95,6 +95,7 @@
 	int flicker;
 	int scale;
 
+	int chip_version;
 	int last_dpms;
 };