Re: can: usb: PEAK-System Technik PCAN-USB specific part

[Marc Kleine-Budde <mkl@pengutronix.de>]

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On 03/07/2012 09:56 AM, Stephane Grosjean wrote:
> Happy to have seen some of you last Monday, at iCC, it was great. It's
> always easier when we're able to attach a face to a name.

Yes, I always like that occasions.

> Back to work now:
> 
> Le 06/03/2012 12:21, Dan Carpenter a écrit :
>> Hello Stephane Grosjean,
>>
>> The patch 46be265d3388: "can: usb: PEAK-System Technik PCAN-USB
>> specific part" from Mar 2, 2012, leads to the following warning:
>>
>> drivers/net/can/usb/peak_usb/pcan_usb.c:751 pcan_usb_encode_msg()
>>      error: wrong number of bits for 'cpu_to_le32' (16 vs 32)
>>
>> drivers/net/can/usb/peak_usb/pcan_usb.c
>>     742          /* can id */
>>     743          if (cf->can_id&  CAN_EFF_FLAG) {
>>     744                  __le32 tmp32 = cpu_to_le32(cf->can_id& 
>> CAN_ERR_MASK);
>>     745
>>     746                  tmp32<<= 3;
>>     747                  *pc |= PCAN_USB_STATUSLEN_EXT_ID;
>>     748                  memcpy(++pc,&tmp32, 4);
>>     749                  pc += 4;
>>     750          } else {
>>     751                  __le16 tmp16 = cpu_to_le32(cf->can_id& 
>> CAN_ERR_MASK);
>>                          ^^^^^^^^^^^^
>> A little endian 32 bit can't fit here.
> 
> 
> How may this error happen while it didn't before? Is this is due to some
> (new) options of gcc, or because of a new version used? In the future,
> how could I avoid that? I mean, how to synchronize with the final GCC
> options/version?

There's no final gcc version. Gcc and the kernel will always evolve.

> 
> FYI, the original code was:
> 
>> >  +    else {
>> } else {
>> >  +        u16 tmp16 = (u16 )*cpu_to_le32*(cf->can_id&  CAN_ERR_MASK);
>>                              ^^^^^^^^^^^^^^^^^
> 
> cf->can_id is a 32-bits field which I want to keep only the lo-word part...
> 
> How to do that in the correct way, please?
> 
> Anyway, what next? I suppose I have to submit a new patch, but comparing
> to what?

Please post your patch against the can-next git repo.

https://gitorious.org/linux-can/linux-can-next

Regards, Marc

-- 
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