From 376d1ea8e48f385954205c517963d602e1e0b7e2 Mon Sep 17 00:00:00 2001
From: Jani Nikula <jani.nikula@intel.com>
Date: Thu, 31 Mar 2022 21:45:08 +0300
Subject: drm/edid: track invalid blocks in drm_do_get_edid()
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Git-commit: ccc97def44ecc087b7c8018f3765467851cd8c80
Patch-mainline: v5.19-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

Track invalid blocks instead of valid extensions to minimize impact on
the happy day scenario, and hide the details in the separate function.

Cc: Ville Syrj채l채 <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrj채l채 <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/6215f85b01c579a44c66129d2b5f41e1ab9294de.1648752228.git.jani.nikula@intel.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/drm_edid.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 73bb2c4a7014..8bf0ae72fd2c 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -1824,9 +1824,10 @@ bool drm_edid_is_valid(struct edid *edid)
 EXPORT_SYMBOL(drm_edid_is_valid);
 
 static struct edid *edid_filter_invalid_blocks(const struct edid *edid,
-					       int valid_extensions)
+					       int invalid_blocks)
 {
 	struct edid *new, *dest_block;
+	int valid_extensions = edid->extensions - invalid_blocks;
 	int i;
 
 	new = kmalloc_array(valid_extensions + 1, EDID_LENGTH, GFP_KERNEL);
@@ -2062,7 +2063,7 @@ struct edid *drm_do_get_edid(struct drm_connector *connector,
 			      size_t len),
 	void *data)
 {
-	int j, valid_extensions = 0;
+	int j, invalid_blocks = 0;
 	struct edid *edid, *new, *override;
 
 	override = drm_get_override_edid(connector);
@@ -2073,12 +2074,10 @@ struct edid *drm_do_get_edid(struct drm_connector *connector,
 	if (!edid)
 		return NULL;
 
-	/* if there's no extensions or no connector, we're done */
-	valid_extensions = edid->extensions;
-	if (valid_extensions == 0)
+	if (edid->extensions == 0)
 		return edid;
 
-	new = krealloc(edid, (valid_extensions + 1) * EDID_LENGTH, GFP_KERNEL);
+	new = krealloc(edid, (edid->extensions + 1) * EDID_LENGTH, GFP_KERNEL);
 	if (!new)
 		goto out;
 	edid = new;
@@ -2095,13 +2094,13 @@ struct edid *drm_do_get_edid(struct drm_connector *connector,
 		}
 
 		if (try == 4)
-			valid_extensions--;
+			invalid_blocks++;
 	}
 
-	if (valid_extensions != edid->extensions) {
+	if (invalid_blocks) {
 		connector_bad_edid(connector, (u8 *)edid, edid->extensions + 1);
 
-		edid = edid_filter_invalid_blocks(edid, valid_extensions);
+		edid = edid_filter_invalid_blocks(edid, invalid_blocks);
 	}
 
 	return edid;
-- 
2.38.1