Hi,
Thanks for your help. I tried this patch and it works well.
So what else I should do? Will you help to merge it to trunk?
Thanks for your help.
Best Regards
Benson
On Fri, Mar 10, 2017 at 7:28 PM, Oliver Neukum <oneukum@xxxxxxxx> wrote:
> Am Freitag, den 10.03.2017, 17:20 +0800 schrieb 家瑋:
>>
>
>
> Hi,
>
>> I have encounter a problem while sending Serial_State packet of
>> CDC-ACM from Linux gadget to Linux host .
>> Here is my question:
>> The environment is a USB device which runs Linux is using
>> CDC-ACM(f_acm.c) to communicate with a Linux host(cdc-acm.c). When
>> device tries to send Serial_State packet to host, host always can't
>> get correct data. I look into the host driver(cdc-acm.c) and found
>> driver calls get_unaligned_le16 on data and this function inverts
>> byte
>> order of data.
>> Following is the link of cdc-acm.c and f_acm.c
>> ACM host: http://lxr.free-electrons.com/source/drivers/usb/class/
>> cdc-acm.c#L325
>> ACM gadget: http://lxr.free-electrons.com/source/drivers/usb/gadge
>> t/function/f_acm.c#L493
>> From the current code, gadget send Serial_State in big-endian but
>> host treat it as little-endian.
>> Is this a problem?
>
> Yes, it is. The gadget driver is exporting its internal endianness.
>
>> Appreciate for your time
>>
> Please test the attached patch.
>
> Regards
> Oliver
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