Hi Rolf,
On Thursday, 17. January 2013 22:49:53 derRolf@xxxxxxxxxxxxxx wrote:
> thanks for your thoughts. Yes, we have our own VID/PID. However, our
> software needs to operate multiple devices with the same VID/PID
> (multi-threaded). The only difference between the devices is the serial
> number, which is unique for each device. We have settings and
> configuration data for the devices, which applies to the specific device
> (i.e. serial number). Depending on the serial number (i.e. device type)
> we boot different FPGA bitstreams.
>
> Actually I don't think any application could be broken by the patch. If
> the device is not found, the code still returns the error. It's just
> that right now the search for the device ends if another device that
> comes first in the list has already been opened. From my point of view
> this is a bug (but one that only happens if you play with multiple
> devices from the same process).
>
> I understand that you don't want to apply any changes before the 1.0
> release. That's fine, I don't use the release code but the git head. But
> it would be good if the patch could be applied after the release is out.
> Right now we have patched our git clone and are merging on each pull
> from upstream.
I've taken a close look at the code in ftdi_usb_open_desc_index().
If I apply your patch in the current form, the -8 and -9 error code
will stop to work.
This can be a problem if there's a permission issue reading
the string descriptors, the function will always return
-3: "device not found" instead of -8 or -9.
How about using ftdi_usb_find_all() to get a list of all your devices.
Then you can try to get the strings via ftdi_usb_get_strings()
and if you f.e. get a serial the device is not in use.
Would that work?
Otherwise we need to come up with a different solution.
Thomas
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