RE: [PATCH v4 05/11] drm/bridge: it6505: increase supports of HDCP repeater ksv devices

[<Hermes.Wu@ite.com.tw>]

>
>
>-----Original Message-----
>From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> 
>Sent: Thursday, September 26, 2024 4:07 PM
>To: Hermes Wu (吳佳宏) <Hermes.Wu@ite.com.tw>
>Cc: Kenneth Hung (洪家倫) <Kenneth.Hung@ite.com.tw>; 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>; Allen Chen <allen.chen@ite.com.tw>; AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>; open list:DRM DRIVERS <dri-devel@lists.freedesktop.org>; open list <linux-kernel@vger.kernel.org>
>Subject: Re: [PATCH v4 05/11] drm/bridge: it6505: increase supports of HDCP repeater ksv devices
>
>On Thu, Sep 26, 2024 at 03:50:14PM GMT, Hermes Wu wrote:
>> From: Hermes Wu <Hermes.wu@ite.com.tw>
>> 
>> A HDCP source shall support max downstream device to 127.
>> 
>> Change definition of MAX_HDCP_DOWN_STREAM_COUNT to 127
>
>This results in struct it6505 growth by ~0.5 KiB. Please mention it in the commit message.
>
>Is it really required to have sha1_input in the constantly allocated structure? I think it's a temporary data, which isn't necessary after processing.
>

For HDCP, KSV list must store for DRM check, constantly allocated is necessary.

>> 
>> Fixes: b5c84a9edcd4 ("drm/bridge: add it6505 driver")
>> Signed-off-by: Hermes Wu <Hermes.wu@ite.com.tw>
>> ---
>>  drivers/gpu/drm/bridge/ite-it6505.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/drivers/gpu/drm/bridge/ite-it6505.c 
>> b/drivers/gpu/drm/bridge/ite-it6505.c
>> index d1f5220e04a6..5d5ce12cd054 100644
>> --- a/drivers/gpu/drm/bridge/ite-it6505.c
>> +++ b/drivers/gpu/drm/bridge/ite-it6505.c
>> @@ -296,7 +296,7 @@
>>  #define MAX_LANE_COUNT 4
>>  #define MAX_LINK_RATE HBR
>>  #define AUTO_TRAIN_RETRY 3
>> -#define MAX_HDCP_DOWN_STREAM_COUNT 10
>> +#define MAX_HDCP_DOWN_STREAM_COUNT 127
>>  #define MAX_CR_LEVEL 0x03
>>  #define MAX_EQ_LEVEL 0x03
>>  #define AUX_WAIT_TIMEOUT_MS 15
>> --
>> 2.34.1
>> 
>
>-- 
>With best wishes
>Dmitry
>

BR,
Hermes