Using maxPacketSize instead of ReportSize is never an option.

maxPacketSize signifies the maximum physical transfer size supported  
by an individual endpoint. This value may be lower, equal, or higher  
than ReportSize. In the last case multiple transfers will be  
conducted to transfer a single report.

If the device defines multiple reports on the same endpoint they  
don't need to have the same size, each single one may have its  
individual size. This is another case where using maxPacketSize will  
fail.

So unless your approach is to accept any report up to maxPacketSize  
it is a bug to use maxPacketSize. And then still you will face  
problems if you have to handle a report that is larger than  
maxPacketSize.

Greetings
Guido


>> Von: Alan Stern <[EMAIL PROTECTED]>
>> Datum: 20. Februar 2007 16:51:04 MEZ
>> An: Robert Marquardt <[EMAIL PROTECTED]>
>> Kopie: [EMAIL PROTECTED],  <[EMAIL PROTECTED]>,  <linux-usb- 
>> [EMAIL PROTECTED]>,  <[EMAIL PROTECTED]>
>> Betreff: Re: [linux-usb-devel] patch usb-iowarrior.patch added to  
>> gregkh-2.6 tree
>>
>> On Tue, 20 Feb 2007, Robert Marquardt wrote:
>>
>>> Robert Marquardt wrote:
>>>> I just found a bug in the IOWarrior hardware. It can report a wrong
>>>> wMaxPacketSize on interface 0. The diff fixes that in the driver.
>>>
>>> To clarify. This is not a bug in the hardware. It is an  
>>> inconsistency,
>>> but it is valid. The problem is that the driver uses wMaxPacketSize
>>> instead of the report size. The diff fixes the driver for now.
>>>
>>> I am unfamiliar with USB driver development so i do not know  
>>> where the
>>> report size is located. It is of course better to use the report  
>>> size
>>> instead of wMaxPacketSize. Then this kludge is not needed.
>>
>> It depends what you want to use it for.  For some purposes it is  
>> better to
>> use the maxpacket value instead of the report size.
>>
>> Alan Stern
>>
>>
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