[Intel-gfx] [PATCH] drm/i915/cnp: Properly handle VBT ddc pin out of bounds.

[Rodrigo Vivi]

If the table result is out of bounds on the array map
there is something really wrong with VBT pin so we don't
return that vbt_pin, but only return 0 instead.

This basically reverts commit 'a8e6f3888b05 ("drm/i915/cnp:
Ignore VBT request for know invalid DDC pin.")'

Also this properly fixes commit 9c3b2689d01f ("drm/i915/cnl:
Map VBT DDC Pin to BSpec DDC Pin.")

Fixes: a8e6f3888b05 ("drm/i915/cnp: Ignore VBT request for know invalid DDC pin.")
Fixes: 9c3b2689d01f ("drm/i915/cnl: Map VBT DDC Pin to BSpec DDC Pin.")
Cc: Radhakrishna Sripada <radhakrishna.sripada at intel.com>
Cc: Jani Nikula <jani.nikula at intel.com>
Cc: Kai Heng Feng <kai.heng.feng at canonical.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
---
 drivers/gpu/drm/i915/intel_bios.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
index 95f0b310d656..844c1e8f574f 100644
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -1115,16 +1115,11 @@ static const u8 cnp_ddc_pin_map[] = {
 
 static u8 map_ddc_pin(struct drm_i915_private *dev_priv, u8 vbt_pin)
 {
-	if (HAS_PCH_CNP(dev_priv)) {
-		if (vbt_pin > 0 && vbt_pin < ARRAY_SIZE(cnp_ddc_pin_map))
-			return cnp_ddc_pin_map[vbt_pin];
-		if (vbt_pin > GMBUS_PIN_4_CNP) {
-			DRM_DEBUG_KMS("Ignoring alternate pin: VBT claims DDC pin %d, which is not valid for this platform\n", vbt_pin);
-			return 0;
-		}
-	}
+	if (HAS_PCH_CNP(dev_priv) &&
+	    vbt_pin > 0 && vbt_pin < ARRAY_SIZE(cnp_ddc_pin_map))
+		return cnp_ddc_pin_map[vbt_pin];
 
-	return vbt_pin;
+	return 0;
 }
 
 static void parse_ddi_port(struct drm_i915_private *dev_priv, enum port port,
-- 
2.13.6