drm/i915/ns2501: Rip out the reenable hack

With the change in the modeset sequence this shouldn't be required
any more since the ->mode_set callback now gets called when the dvo
port is fully up and running.

Also limit the retry loop to 10 tries to avoid hanging the machine
while holding important modeset locks.

Cc: Thomas Richter <thor@math.tu-berlin.de>
Tested-by: Thomas Richter <thor@math.tu-berlin.de>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/dvo_ns2501.c

@@ -87,49 +87,6 @@ struct ns2501_priv {
  * when switching the resolution.
  */
 
-static void enable_dvo(struct intel_dvo_device *dvo)
-{
-	struct ns2501_priv *ns = (struct ns2501_priv *)(dvo->dev_priv);
-	struct i2c_adapter *adapter = dvo->i2c_bus;
-	struct intel_gmbus *bus = container_of(adapter,
-					       struct intel_gmbus,
-					       adapter);
-	struct drm_i915_private *dev_priv = bus->dev_priv;
-
-	DRM_DEBUG_KMS("%s: Trying to re-enable the DVO\n", __FUNCTION__);
-
-	ns->dvoc = I915_READ(DVO_C);
-	ns->pll_a = I915_READ(_DPLL_A);
-	ns->srcdim = I915_READ(DVOC_SRCDIM);
-	ns->fw_blc = I915_READ(FW_BLC);
-
-	I915_WRITE(DVOC, 0x10004084);
-	I915_WRITE(_DPLL_A, 0xd0820000);
-	I915_WRITE(DVOC_SRCDIM, 0x400300);	// 1024x768
-	I915_WRITE(FW_BLC, 0x1080304);
-
-	I915_WRITE(DVOC, 0x90004084);
-}
-
-/*
- * Restore the I915 registers modified by the above
- * trigger function.
- */
-static void restore_dvo(struct intel_dvo_device *dvo)
-{
-	struct i2c_adapter *adapter = dvo->i2c_bus;
-	struct intel_gmbus *bus = container_of(adapter,
-					       struct intel_gmbus,
-					       adapter);
-	struct drm_i915_private *dev_priv = bus->dev_priv;
-	struct ns2501_priv *ns = (struct ns2501_priv *)(dvo->dev_priv);
-
-	I915_WRITE(DVOC, ns->dvoc);
-	I915_WRITE(_DPLL_A, ns->pll_a);
-	I915_WRITE(DVOC_SRCDIM, ns->srcdim);
-	I915_WRITE(FW_BLC, ns->fw_blc);
-}
-
 /*
 ** Read a register from the ns2501.
 ** Returns true if successful, false otherwise.
@@ -300,7 +257,7 @@ static void ns2501_mode_set(struct intel_dvo_device *dvo,
 			    struct drm_display_mode *adjusted_mode)
 {
 	bool ok;
-	bool restore = false;
+	int retries = 10;
 	struct ns2501_priv *ns = (struct ns2501_priv *)(dvo->dev_priv);
 
 	DRM_DEBUG_KMS
@@ -476,20 +433,7 @@ static void ns2501_mode_set(struct intel_dvo_device *dvo,
 			ns->reg_8_shadow |= NS2501_8_BPAS;
 		}
 		ok &= ns2501_writeb(dvo, NS2501_REG8, ns->reg_8_shadow);
-
-		if (!ok) {
-			if (restore)
-				restore_dvo(dvo);
-			enable_dvo(dvo);
-			restore = true;
-		}
-	} while (!ok);
-	/*
-	 * Restore the old i915 registers before
-	 * forcing the ns2501 on.
-	 */
-	if (restore)
-		restore_dvo(dvo);
+	} while (!ok && retries--);
 }
 
 /* set the NS2501 power state */
@@ -510,7 +454,7 @@ static bool ns2501_get_hw_state(struct intel_dvo_device *dvo)
 static void ns2501_dpms(struct intel_dvo_device *dvo, bool enable)
 {
 	bool ok;
-	bool restore = false;
+	int retries = 10;
 	struct ns2501_priv *ns = (struct ns2501_priv *)(dvo->dev_priv);
 	unsigned char ch;
 
@@ -537,16 +481,7 @@ static void ns2501_dpms(struct intel_dvo_device *dvo, bool enable)
 			ok &=
 			    ns2501_writeb(dvo, 0x35,
 					  enable ? 0xff : 0x00);
-			if (!ok) {
-				if (restore)
-					restore_dvo(dvo);
-				enable_dvo(dvo);
-				restore = true;
-			}
-		} while (!ok);
-
-		if (restore)
-			restore_dvo(dvo);
+		} while (!ok && retries--);
 	}
 }