From: Hermes Wu <Hermes.wu@ite.com.tw>
Date: Tue, 21 Jan 2025 07:01:51 +0000 (+0800)
Subject: drm/bridge: it6505: fix HDCP V match check is not performed correctly
X-Git-Tag: v6.15-rc1~120^2~20^2~40
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a5072fc77fb9e38fa9fd883642c83c3720049159;p=thirdparty%2Flinux.git

drm/bridge: it6505: fix HDCP V match check is not performed correctly

Fix a typo where V compare incorrectly compares av[] with av[] itself,
which can result in HDCP failure.

The loop of V compare is expected to iterate for 5 times
which compare V array form av[0][] to av[4][].
It should check loop counter reach the last statement "i == 5"
before return true

Fixes: 0989c02c7a5c ("drm/bridge: it6505: fix HDCP CTS compare V matching")
Signed-off-by: Hermes Wu <Hermes.wu@ite.com.tw>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20250121-fix-hdcp-v-comp-v4-1-185f45c728dc@ite.com.tw
---

diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
index 88ef76a37fe6a..76dabca04d0d1 100644
--- a/drivers/gpu/drm/bridge/ite-it6505.c
+++ b/drivers/gpu/drm/bridge/ite-it6505.c
@@ -2250,12 +2250,13 @@ static bool it6505_hdcp_part2_ksvlist_check(struct it6505 *it6505)
 			continue;
 		}
 
-		for (i = 0; i < 5; i++) {
+		for (i = 0; i < 5; i++)
 			if (bv[i][3] != av[i][0] || bv[i][2] != av[i][1] ||
-			    av[i][1] != av[i][2] || bv[i][0] != av[i][3])
+			    bv[i][1] != av[i][2] || bv[i][0] != av[i][3])
 				break;
 
-			DRM_DEV_DEBUG_DRIVER(dev, "V' all match!! %d, %d", retry, i);
+		if (i == 5) {
+			DRM_DEV_DEBUG_DRIVER(dev, "V' all match!! %d", retry);
 			return true;
 		}
 	}