[PATCH] staging: typec: Fix type mismatch found with sparse

[Guenter Roeck]

On 07/05/2017 07:57 PM, Thomas Gardner wrote:
> Guenter Roeck<linux at roeck-us.net> / 2017-07-05T07:25-0700
>> On 07/05/2017 07:00 AM, Thomas Gardner wrote:
>>> The warning below is resolved by casting the LHS to __le32.
>>>
>>> typec/tcpm.c:1019:49: warning: incorrect type in assignment (different base types)
>>> typec/tcpm.c:1019:49:    expected unsigned int [unsigned] [usertype] <noident>
>>> typec/tcpm.c:1019:49:    got restricted __le32 [usertype] <noident>
>>>
>>> Signed-off-by: Thomas Gardner <tmg at fastmail.com>
>>> ---
>>>    drivers/staging/typec/tcpm.c | 2 +-
>>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/staging/typec/tcpm.c b/drivers/staging/typec/tcpm.c
>>> index 20eb4ebcf8c3..7699bb27a4d9 100644
>>> --- a/drivers/staging/typec/tcpm.c
>>> +++ b/drivers/staging/typec/tcpm.c
>>> @@ -1015,7 +1015,7 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
>>>    			if (port->data_role == TYPEC_DEVICE &&
>>>    			    port->nr_snk_vdo) {
>>>    				for (i = 0; i <  port->nr_snk_vdo; i++)
>>> -					response[i + 1]
>>> +					((__le32 *)response)[i + 1]
>>>    						= cpu_to_le32(port->snk_vdo[i]);
>>>    				rlen = port->nr_snk_vdo + 1;
>>>    			}
>>>
>> I think this would just hide a number of at least potential endianness issues
>> in the driver. response[] should be of type __le32 instead, with everything
>> that comes with it.
> 
> Greetings Guenter, is this conversion actually necessary? The state
> machine tries to fix endianness of the response before sending at,
> 
> 	for (i = 0; i < port->vdo_count; i++)
> 		msg.payload[i] = cpu_to_le32(port->vdo_data[i]);
> 
> Perhaps the patch should be,
> 
> -	response[i + 1]
> -		= cpu_to_le32(port->snk_vdo[i]);
> +	response[i + 1] = port->snk_vdo[i];
> 
> which also clears the warning.
> 

Yes, looking through the code, that is correct.

Thanks for tracking this down. Can you send an updated patch ?

Guenter

>> Which makes me wonder, since I don't see any of those warnings - what
>> does it take to see them ?
> 
> I can see them by running,
> 
> 	make C=2 ./drivers/staging/typec/
> 
>> Guenter
> 
> 
> 
>