[PATCH] drm/edid: Only print the bad edid when aborting

[Chris Wilson]

Currently, if drm.debug is enabled, we get a DRM_ERROR message on the
intermediate edid reads. This causes transient failures in CI which
flags up the sporadic EDID read failures, which are recovered by
rereading the EDID automatically. This patch combines the reporting done
by drm_do_get_edid() itself with the bad block printing from
get_edid_block(), into a single warning associated with the connector
once all attempts to retrieve the EDID fail.

References: https://bugs.freedesktop.org/show_bug.cgi?id=98228
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/drm_edid.c | 82 +++++++++++++++++++++++++---------------------
 1 file changed, 44 insertions(+), 38 deletions(-)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index ec77bd3e1f08..51dd10c65b53 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -1260,6 +1260,26 @@ drm_do_probe_ddc_edid(void *data, u8 *buf, unsigned int block, size_t len)
 	return ret == xfers ? 0 : -1;
 }
 
+static void connector_add_bad_edid(struct drm_connector *connector,
+				   u8 *block, int num)
+{
+	if (connector->bad_edid_counter++ && !(drm_debug & DRM_UT_KMS))
+		return;
+
+	if (drm_edid_is_zero(block, EDID_LENGTH)) {
+		dev_warn(connector->dev->dev,
+			 "%s: EDID block %d is all zeroes.\n",
+			 connector->name, num);
+	} else {
+		dev_warn(connector->dev->dev,
+			 "%s: EDID block %d invalid:\n",
+			 connector->name, num);
+		print_hex_dump(KERN_WARNING,
+			       " \t", DUMP_PREFIX_NONE, 16, 1,
+			       block, EDID_LENGTH, false);
+	}
+}
+
 /**
  * drm_do_get_edid - get EDID data using a custom EDID block read function
  * @connector: connector we're probing
@@ -1282,20 +1302,19 @@ struct edid *drm_do_get_edid(struct drm_connector *connector,
 	void *data)
 {
 	int i, j = 0, valid_extensions = 0;
-	u8 *block, *new;
-	bool print_bad_edid = !connector->bad_edid_counter || (drm_debug & DRM_UT_KMS);
+	u8 *edid, *new;
 
-	if ((block = kmalloc(EDID_LENGTH, GFP_KERNEL)) == NULL)
+	if ((edid = kmalloc(EDID_LENGTH, GFP_KERNEL)) == NULL)
 		return NULL;
 
 	/* base block fetch */
 	for (i = 0; i < 4; i++) {
-		if (get_edid_block(data, block, 0, EDID_LENGTH))
+		if (get_edid_block(data, edid, 0, EDID_LENGTH))
 			goto out;
-		if (drm_edid_block_valid(block, 0, print_bad_edid,
+		if (drm_edid_block_valid(edid, 0, false,
 					 &connector->edid_corrupt))
 			break;
-		if (i == 0 && drm_edid_is_zero(block, EDID_LENGTH)) {
+		if (i == 0 && drm_edid_is_zero(edid, EDID_LENGTH)) {
 			connector->null_edid_counter++;
 			goto carp;
 		}
@@ -1304,58 +1323,45 @@ struct edid *drm_do_get_edid(struct drm_connector *connector,
 		goto carp;
 
 	/* if there's no extensions, we're done */
-	if (block[0x7e] == 0)
-		return (struct edid *)block;
+	if (edid[0x7e] == 0)
+		return (struct edid *)edid;
 
-	new = krealloc(block, (block[0x7e] + 1) * EDID_LENGTH, GFP_KERNEL);
+	new = krealloc(edid, (edid[0x7e] + 1) * EDID_LENGTH, GFP_KERNEL);
 	if (!new)
 		goto out;
-	block = new;
+	edid = new;
+
+	for (j = 1; j <= edid[0x7e]; j++) {
+		u8 *block = edid + (valid_extensions + 1) * EDID_LENGTH;
 
-	for (j = 1; j <= block[0x7e]; j++) {
 		for (i = 0; i < 4; i++) {
-			if (get_edid_block(data,
-				  block + (valid_extensions + 1) * EDID_LENGTH,
-				  j, EDID_LENGTH))
+			if (get_edid_block(data, block, j, EDID_LENGTH))
 				goto out;
-			if (drm_edid_block_valid(block + (valid_extensions + 1)
-						 * EDID_LENGTH, j,
-						 print_bad_edid,
-						 NULL)) {
+			if (drm_edid_block_valid(block, j, false, NULL)) {
 				valid_extensions++;
 				break;
 			}
 		}
 
-		if (i == 4 && print_bad_edid) {
-			dev_warn(connector->dev->dev,
-			 "%s: Ignoring invalid EDID block %d.\n",
-			 connector->name, j);
-
-			connector->bad_edid_counter++;
-		}
+		if (i == 4)
+			connector_add_bad_edid(connector, block, j);
 	}
 
-	if (valid_extensions != block[0x7e]) {
-		block[EDID_LENGTH-1] += block[0x7e] - valid_extensions;
-		block[0x7e] = valid_extensions;
-		new = krealloc(block, (valid_extensions + 1) * EDID_LENGTH, GFP_KERNEL);
+	if (valid_extensions != edid[0x7e]) {
+		edid[EDID_LENGTH-1] += edid[0x7e] - valid_extensions;
+		edid[0x7e] = valid_extensions;
+		new = krealloc(edid, (valid_extensions + 1) * EDID_LENGTH, GFP_KERNEL);
 		if (!new)
 			goto out;
-		block = new;
+		edid = new;
 	}
 
-	return (struct edid *)block;
+	return (struct edid *)edid;
 
 carp:
-	if (print_bad_edid) {
-		dev_warn(connector->dev->dev, "%s: EDID block %d invalid.\n",
-			 connector->name, j);
-	}
-	connector->bad_edid_counter++;
-
+	connector_add_bad_edid(connector, edid, 0);
 out:
-	kfree(block);
+	kfree(edid);
 	return NULL;
 }
 EXPORT_SYMBOL_GPL(drm_do_get_edid);
-- 
2.9.3