hi
>
>-----Original Message-----
>From: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
>Sent: Wednesday, January 8, 2025 6:43 PM
>To: Hermes Wu (吳佳宏) <Hermes.Wu@xxxxxxxxxx>
>Cc: Andrzej Hajda <andrzej.hajda@xxxxxxxxx>; Neil Armstrong <neil.armstrong@xxxxxxxxxx>; Robert Foss <rfoss@xxxxxxxxxx>; Laurent Pinchart <Laurent.pinchart@xxxxxxxxxxxxxxxx>; Jonas Karlman <jonas@xxxxxxxxx>; Jernej Skrabec <jernej.skrabec@xxxxxxxxx>; Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>; Maxime Ripard <mripard@xxxxxxxxxx>; Thomas Zimmermann <tzimmermann@xxxxxxx>; David Airlie <airlied@xxxxxxxxx>; Simona Vetter <simona@xxxxxxxx>; AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>; dri-devel@xxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Pet Weng (翁玉芬) <Pet.Weng@xxxxxxxxxx>; Kenneth Hung (洪家倫) <Kenneth.Hung@xxxxxxxxxx>; treapking@xxxxxxxxxxxx
>Subject: Re: [PATCH] drm/bridge: it6505: fix HDCP V match check is not performed correctly
>
>On Wed, Jan 08, 2025 at 01:45:14PM +0800, Hermes Wu via B4 Relay wrote:
>> From: Hermes Wu <Hermes.wu@xxxxxxxxxx>
>>
>> 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 before return
>> true
>>
>> Fixes: 0989c02c7a5c ("drm/bridge: it6505: fix HDCP CTS compare V
>> matching")
>>
>> Signed-off-by: Hermes Wu <Hermes.wu@xxxxxxxxxx>
>
>No empty lines between tags, please.
>
>> ---
>> drivers/gpu/drm/bridge/ite-it6505.c | 9 ++++++---
>> 1 file changed, 6 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/ite-it6505.c
>> b/drivers/gpu/drm/bridge/ite-it6505.c
>> index
>> 88ef76a37fe6accacdd343839ff2569b31b18ceb..e87247aea1d2ffbdad192e241056
>> d34fdfb32163 100644
>> --- a/drivers/gpu/drm/bridge/ite-it6505.c
>> +++ b/drivers/gpu/drm/bridge/ite-it6505.c
>> @@ -2254,9 +2254,12 @@ static bool it6505_hdcp_part2_ksvlist_check(struct it6505 *it6505)
>> 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);
>> - return true;
>> + if (i == 4) {
>
>I think there was a similar patch yesteday.
I can't find patch for it6505, would you provide link?
If it also fixes this bug, should I just drop this patch?
>Anyway, I have exactly the same feedback: please pull this out of the loop, this is how it's usually checked / done.
>
I will move it out the loop,
Thanks.
>> + 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@xxxxxxxxxx>
>>
>>
>
>--
>With best wishes
>Dmitry
>
BR,
Hermes
