Re: [Qemu-devel] [PATCH RESEND 1/3] usb-ccid: make ccid_write_data_block() cope with null buffers

[Gerd Hoffmann]

  Hi,

> > +    if (len == 0) {
> > +        return;
> 
> Correct only if messages without data always have the same meaning as no
> message.  Gerd?

Not a ccid expert, but looking through the code it seems writing a
(reply) data block with status and without payload (data = NULL and len
= 0) is perfectly fine and can happen in case no (virtual) smartcard is
inserted into the card reader.  Which this patch breaks.  So,

NACK.

cheers,
  Gerd