[PATCH v3] drm/bridge: it6505: fix HDCP V match check is not performed correctly

[PATCH v3] drm/bridge: it6505: fix HDCP V match check is not performed correctly

[Hermes Wu via B4 Relay]

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

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")
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Hermes Wu <Hermes.wu@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 | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
index 88ef76a37fe6accacdd343839ff2569b31b18ceb..2f82fbc0b8bf8c322c088dc257720c6825651bb8 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])
 				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>

Re: [PATCH v3] drm/bridge: it6505: fix HDCP V match check is not performed correctly

[Dmitry Baryshkov]

On Thu, Jan 09, 2025 at 02:40:08PM +0800, Hermes Wu via B4 Relay wrote:
> From: Hermes Wu <Hermes.wu@ite.com.tw>
> 
> 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")
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

Excuse me, where did you get that from?? I didn't r-b it (yet).


> Signed-off-by: Hermes Wu <Hermes.wu@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 | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 

-- 
With best wishes
Dmitry

RE: [PATCH v3] drm/bridge: it6505: fix HDCP V match check is not performed correctly

[Hermes.Wu]

hi


-----Original Message-----
From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> 
Sent: Thursday, January 9, 2025 9:09 PM
To: Hermes Wu (吳佳宏) <Hermes.Wu@ite.com.tw>
Cc: Andrzej Hajda <andrzej.hajda@intel.com>; Neil Armstrong <neil.armstrong@linaro.org>; Robert Foss <rfoss@kernel.org>; Laurent Pinchart <Laurent.pinchart@ideasonboard.com>; Jonas Karlman <jonas@kwiboo.se>; Jernej Skrabec <jernej.skrabec@gmail.com>; Maarten Lankhorst <maarten.lankhorst@linux.intel.com>; Maxime Ripard <mripard@kernel.org>; Thomas Zimmermann <tzimmermann@suse.de>; David Airlie <airlied@gmail.com>; Simona Vetter <simona@ffwll.ch>; AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>; dri-devel@lists.freedesktop.org; linux-kernel@vger.kernel.org; Pet Weng (翁玉芬) <Pet.Weng@ite.com.tw>; Kenneth Hung (洪家倫) <Kenneth.Hung@ite.com.tw>; treapking@chromium.org
Subject: Re: [PATCH v3] drm/bridge: it6505: fix HDCP V match check is not performed correctly

On Thu, Jan 09, 2025 at 02:40:08PM +0800, Hermes Wu via B4 Relay wrote:
> From: Hermes Wu <Hermes.wu@ite.com.tw>
> 
> 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")
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
>Excuse me, where did you get that from?? I didn't r-b it (yet).

Sorry,

I think I just missing understanding about this tag.
I thought it should add if someone give advice to a path.

So I add it before you r-b it,

> Signed-off-by: Hermes Wu <Hermes.wu@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@i
> te.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@i
> te.com.tw
> ---
>  drivers/gpu/drm/bridge/ite-it6505.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
>--
>With best wishes
>Dmitry

Br.
Hermes

Re: [PATCH v3] drm/bridge: it6505: fix HDCP V match check is not performed correctly

[Dmitry Baryshkov]

On Fri, Jan 10, 2025 at 02:00:35AM +0000, Hermes.Wu@ite.com.tw wrote:
> hi
> 
> 
> -----Original Message-----
> From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> 
> Sent: Thursday, January 9, 2025 9:09 PM
> To: Hermes Wu (吳佳宏) <Hermes.Wu@ite.com.tw>
> Cc: Andrzej Hajda <andrzej.hajda@intel.com>; Neil Armstrong <neil.armstrong@linaro.org>; Robert Foss <rfoss@kernel.org>; Laurent Pinchart <Laurent.pinchart@ideasonboard.com>; Jonas Karlman <jonas@kwiboo.se>; Jernej Skrabec <jernej.skrabec@gmail.com>; Maarten Lankhorst <maarten.lankhorst@linux.intel.com>; Maxime Ripard <mripard@kernel.org>; Thomas Zimmermann <tzimmermann@suse.de>; David Airlie <airlied@gmail.com>; Simona Vetter <simona@ffwll.ch>; AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>; dri-devel@lists.freedesktop.org; linux-kernel@vger.kernel.org; Pet Weng (翁玉芬) <Pet.Weng@ite.com.tw>; Kenneth Hung (洪家倫) <Kenneth.Hung@ite.com.tw>; treapking@chromium.org
> Subject: Re: [PATCH v3] drm/bridge: it6505: fix HDCP V match check is not performed correctly
> 
> On Thu, Jan 09, 2025 at 02:40:08PM +0800, Hermes Wu via B4 Relay wrote:
> > From: Hermes Wu <Hermes.wu@ite.com.tw>
> > 
> > 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")
> > Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> >Excuse me, where did you get that from?? I didn't r-b it (yet).
> 
> Sorry,
> 
> I think I just missing understanding about this tag.
> I thought it should add if someone give advice to a path.
> 
> So I add it before you r-b it,

Okay. Please don't add extra tags in future.

The patch itself is:


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


> 
> > Signed-off-by: Hermes Wu <Hermes.wu@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@i
> > te.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@i
> > te.com.tw
> > ---
> >  drivers/gpu/drm/bridge/ite-it6505.c | 5 +++--
> >  1 file changed, 3 insertions(+), 2 deletions(-)
> > 
> >--
> >With best wishes
> >Dmitry
> 
> Br.
> Hermes

-- 
With best wishes
Dmitry