From 27509dc2a13822550412e1ce3bd2441c28948f4e Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Thu, 9 Sep 2010 19:06:13 +0100
Subject: [PATCH] --- yaml --- r: 218007 b: refs/heads/master c:
 b5c616a75428d85f92407e4509553f937b720630 h: refs/heads/master i:   218005:
 67214c849369a9d32b0309e0ed5f711c06ddd5f5   218003:
 1b779af324a79d1346ebef2aa7b49f9d386c944c   217999:
 f36d5437138bb39ac68a7aac5fc0c98ed8c6ae43 v: v3

---
 [refs]                                  |  2 +-
 trunk/drivers/gpu/drm/i915/intel_sdvo.c | 71 +++++++++++++------------
 2 files changed, 37 insertions(+), 36 deletions(-)

diff --git a/[refs] b/[refs]
index 480a30a5d6ab..847cdd51eb5c 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: ec5da01e23eec303dd313aa62b8ed4712c488437
+refs/heads/master: b5c616a75428d85f92407e4509553f937b720630
diff --git a/trunk/drivers/gpu/drm/i915/intel_sdvo.c b/trunk/drivers/gpu/drm/i915/intel_sdvo.c
index 96952d20cd21..a812d65fa31e 100644
--- a/trunk/drivers/gpu/drm/i915/intel_sdvo.c
+++ b/trunk/drivers/gpu/drm/i915/intel_sdvo.c
@@ -462,54 +462,55 @@ static const char *cmd_status_names[] = {
 	"Scaling not supported"
 };
 
-static void intel_sdvo_debug_response(struct intel_sdvo *intel_sdvo,
-				      void *response, int response_len,
-				      u8 status)
+static bool intel_sdvo_read_response(struct intel_sdvo *intel_sdvo,
+				     void *response, int response_len)
 {
+	u8 retry = 5;
+	u8 status;
 	int i;
 
+	/*
+	 * The documentation states that all commands will be
+	 * processed within 15µs, and that we need only poll
+	 * the status byte a maximum of 3 times in order for the
+	 * command to be complete.
+	 *
+	 * Check 5 times in case the hardware failed to read the docs.
+	 */
+	do {
+		if (!intel_sdvo_read_byte(intel_sdvo,
+					  SDVO_I2C_CMD_STATUS,
+					  &status))
+			return false;
+	} while (status == SDVO_CMD_STATUS_PENDING && --retry);
+
 	DRM_DEBUG_KMS("%s: R: ", SDVO_NAME(intel_sdvo));
-	for (i = 0; i < response_len; i++)
-		DRM_LOG_KMS("%02X ", ((u8 *)response)[i]);
-	for (; i < 8; i++)
-		DRM_LOG_KMS("   ");
 	if (status <= SDVO_CMD_STATUS_SCALING_NOT_SUPP)
 		DRM_LOG_KMS("(%s)", cmd_status_names[status]);
 	else
 		DRM_LOG_KMS("(??? %d)", status);
-	DRM_LOG_KMS("\n");
-}
 
-static bool intel_sdvo_read_response(struct intel_sdvo *intel_sdvo,
-				     void *response, int response_len)
-{
-	int i;
-	u8 status;
-	u8 retry = 50;
-
-	while (retry--) {
-		/* Read the command response */
-		for (i = 0; i < response_len; i++) {
-			if (!intel_sdvo_read_byte(intel_sdvo,
-						  SDVO_I2C_RETURN_0 + i,
-						  &((u8 *)response)[i]))
-				return false;
-		}
+	if (status != SDVO_CMD_STATUS_SUCCESS)
+		goto log_fail;
 
-		/* read the return status */
-		if (!intel_sdvo_read_byte(intel_sdvo, SDVO_I2C_CMD_STATUS,
-					  &status))
-			return false;
+	/* Read the command response */
+	for (i = 0; i < response_len; i++) {
+		if (!intel_sdvo_read_byte(intel_sdvo,
+					  SDVO_I2C_RETURN_0 + i,
+					  &((u8 *)response)[i]))
+			goto log_fail;
+		DRM_LOG_KMS("%02X ", ((u8 *)response)[i]);
+	}
 
-		intel_sdvo_debug_response(intel_sdvo, response, response_len,
-					  status);
-		if (status != SDVO_CMD_STATUS_PENDING)
-			break;
+	for (; i < 8; i++)
+		DRM_LOG_KMS("   ");
+	DRM_LOG_KMS("\n");
 
-		mdelay(50);
-	}
+	return true;
 
-	return status == SDVO_CMD_STATUS_SUCCESS;
+log_fail:
+	DRM_LOG_KMS("\n");
+	return false;
 }
 
 static int intel_sdvo_get_pixel_multiplier(struct drm_display_mode *mode)