Re: [Qemu-devel] [PATCH 9/9] usb: mtp: reply INCOMPLETE_TRANSFER on read errors

[Peter Wu]

On Friday 25 April 2014 12:48:14 Gerd Hoffmann wrote:
> Signed-off-by: Gerd Hoffmann <address@hidden>
> ---
>  hw/usb/dev-mtp.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/usb/dev-mtp.c b/hw/usb/dev-mtp.c
> index 6bd6a82..8e1a1b7 100644
> --- a/hw/usb/dev-mtp.c
> +++ b/hw/usb/dev-mtp.c
> @@ -50,6 +50,7 @@ enum mtp_code {
>      RES_INVALID_TRANSACTION_ID     = 0x2004,
>      RES_OPERATION_NOT_SUPPORTED    = 0x2005,
>      RES_PARAMETER_NOT_SUPPORTED    = 0x2006,
> +    RES_INCOMPLETE_TRANSFER        = 0x2007,
>      RES_INVALID_STORAGE_ID         = 0x2008,
>      RES_INVALID_OBJECT_HANDLE      = 0x2009,
>      RES_SPEC_BY_FORMAT_UNSUPPORTED = 0x2014,
> @@ -946,7 +947,7 @@ static void usb_mtp_handle_data(USBDevice *dev, USBPacket 
> *p) }
>                  rc = read(d->fd, d->data, dlen);
>                  if (rc != dlen) {
> -                    fprintf(stderr, "%s: TODO: handle read error\n", 
> __func__);
> +                    s->result->code = RES_INCOMPLETE_TRANSFER;
>                  }
>                  usb_packet_copy(p, d->data, dlen);
>              }

The bogus data packet is sent with usb_packet_copy, shouldn't you return
USB_RET_NAK for now? Something like:

if (rc == dlen) {
    usb_packet_copy(p, d->data, dlen);
} else {
    s->result->code = RES_INCOMPLETE_TRANSFER;
    dlen = 0;
}

dlen = 0 to avoid messing with the offset.

Kind regards,
Peter