drm/i915: Add reverse mapping between port and intel_encoder

This patch adds a reverse mapping from a digital port number to
intel_encoder object containing the corresponding intel_digital_port.
It simplifies the query of the encoder a lot.

Note that, even if it's a valid digital port, the dig_port_map[] might
point still to NULL -- usually it implies a DP MST port.  Due to this
fact, the NULL check in each place has no WARN_ON() and just skips the
port.  Once when the situation changes in future, we might introduce
WARN_ON() for a more strict check.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 15c6dc0b4f37..9dbc143cac27 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1944,6 +1944,8 @@ struct drm_i915_private {
 	/* perform PHY state sanity checks? */
 	bool chv_phy_assert[2];
 
+	struct intel_encoder *dig_port_map[I915_MAX_PORTS];
+
 	/*
 	 * NOTE: This is the dri1/ums dungeon, don't add stuff here. Your patch
 	 * will be rejected. Instead look for a better place.