From: Hermes Wu <Hermes.wu@ite.com.tw>

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>
---
Changes in v4:
- Fix a typo where V compare incorrectly compares av[] with av[] itself
- Link to v3: https://lore.kernel.org/r/20250109-fix-hdcp-v-comp-v3-1-1258edb249ab@ite.com.tw

Changes in v3:
- The V value compare loop from i = 0 to i = 4 and shall exit with i == 5 
  if all V element matches
- Link to v2: https://lore.kernel.org/r/20250109-fix-hdcp-v-comp-v2-1-7dce0a59523f@ite.com.tw

Changes in v2:
- pull the check of statment "i" out of V value check loop 
- Link to v1: https://lore.kernel.org/r/20250108-fix-hdcp-v-comp-v1-1-9404811825cd@ite.com.tw
---
 drivers/gpu/drm/bridge/ite-it6505.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
index 88ef76a37fe6accacdd343839ff2569b31b18ceb..76dabca04d0d191b3bdee23c6a3e55f4b6d3bad4 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;
 		}
 	}

---
base-commit: 938fbb16aba8f7b88e0fdcf56f315a5bbad41aad
change-id: 20250107-fix-hdcp-v-comp-3ba8e3d7adf3

Best regards,
-- 
Hermes Wu <Hermes.wu@ite.com.tw>

On Tue, 21 Jan 2025 15:01:51 +0800, Hermes Wu wrote:
> 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
> 
> [...]

Applied, thanks!

[1/1] drm/bridge: it6505: fix HDCP V match check is not performed correctly
      https://gitlab.freedesktop.org/drm/misc/kernel/-/commit/a5072fc77fb9



Rob

On Tue, Jan 21, 2025 at 03:01:51PM +0800, Hermes Wu via B4 Relay wrote:
> From: Hermes Wu <Hermes.wu@ite.com.tw>
> 
> 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>
> ---
> Changes in v4:
> - Fix a typo where V compare incorrectly compares av[] with av[] itself
> - Link to v3: https://lore.kernel.org/r/20250109-fix-hdcp-v-comp-v3-1-1258edb249ab@ite.com.tw
> 
> Changes in v3:
> - The V value compare loop from i = 0 to i = 4 and shall exit with i == 5 
>   if all V element matches
> - Link to v2: https://lore.kernel.org/r/20250109-fix-hdcp-v-comp-v2-1-7dce0a59523f@ite.com.tw
> 
> Changes in v2:
> - pull the check of statment "i" out of V value check loop 
> - Link to v1: https://lore.kernel.org/r/20250108-fix-hdcp-v-comp-v1-1-9404811825cd@ite.com.tw
> ---
>  drivers/gpu/drm/bridge/ite-it6505.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

-- 
With best wishes
Dmitry