linux-kernel - RE: [PATCH v4 02/11] drm/bridge: it6505: fix aux operation for edid read

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <3150e8e9ca754411bb0404475d149a8f@ite.com.tw>
Date: Thu, 26 Sep 2024 08:04:32 +0000
From: <Hermes.Wu@....com.tw>
To: <dmitry.baryshkov@...aro.org>
CC: <Kenneth.Hung@....com.tw>, <andrzej.hajda@...el.com>,
        <neil.armstrong@...aro.org>, <rfoss@...nel.org>,
        <Laurent.pinchart@...asonboard.com>, <jonas@...boo.se>,
        <jernej.skrabec@...il.com>, <maarten.lankhorst@...ux.intel.com>,
        <mripard@...nel.org>, <tzimmermann@...e.de>, <airlied@...il.com>,
        <simona@...ll.ch>, <angelogioacchino.delregno@...labora.com>,
        <dri-devel@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH v4 02/11] drm/bridge: it6505: fix aux operation for edid
 read

>On Thu, Sep 26, 2024 at 03:47:52PM GMT, Hermes Wu wrote:
>> From: Hermes Wu <Hermes.wu@....com.tw>
>> 
>> The EDID read operation can reach the maximum size of the AUX FIFO buffer.
>
>And? Commit message should describe why the change is necessary and what is being done. Just providing a statement is not enough.
>

The original AUX operation treat all reads by using data registers will be limited at 4 bytes.
AUX operation command CMD_AUX_I2C_EDID_READ using AUX FIFO is capable of reads data by 16 bytes each time.
It can improve speed of read EDID.


>> 
>> Fixes: b5c84a9edcd4 ("drm/bridge: add it6505 driver")
>> Signed-off-by: Hermes Wu <Hermes.wu@....com.tw>
>> ---
>>  drivers/gpu/drm/bridge/ite-it6505.c | 8 ++++++--
>>  1 file changed, 6 insertions(+), 2 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/bridge/ite-it6505.c 
>> b/drivers/gpu/drm/bridge/ite-it6505.c
>> index 28a8043229d3..b451d3c2ac1d 100644
>> --- a/drivers/gpu/drm/bridge/ite-it6505.c
>> +++ b/drivers/gpu/drm/bridge/ite-it6505.c
>> @@ -1078,8 +1078,11 @@ static ssize_t it6505_aux_do_transfer(struct it6505 *it6505,
>>  	int i, ret_size, ret = 0, request_size;
>>  
>>  	mutex_lock(&it6505->aux_lock);
>> -	for (i = 0; i < size; i += 4) {
>> -		request_size = min((int)size - i, 4);
>> +	for (i = 0; i < size; ) {
>> +		if (cmd == CMD_AUX_I2C_EDID_READ)
>> +			request_size = min_t(int, (int)size - i, AUX_FIFO_MAX_SIZE);
>> +		else
>> +			request_size = min_t(int, (int)size - i, 4);
>>  		ret_size = it6505_aux_operation(it6505, cmd, address + i,
>>  						buffer + i, request_size,
>>  						reply);
>> @@ -1088,6 +1091,7 @@ static ssize_t it6505_aux_do_transfer(struct it6505 *it6505,
>>  			goto aux_op_err;
>>  		}
>>  
>> +		i += request_size;
>>  		ret += ret_size;
>>  	}
>>  
>> --
>> 2.34.1
>> 
>
>-- 
>With best wishes
>Dmitry
>

BR,
Hermes