On Tue, 14 Jul 2015, Bernd Porr wrote: > I've got a question regarding ISO transfer. If the firmware is not > providing data is the ISO urb returning zero packet length and if yes > how can I check that in the driver? I'm working on a solution for my > USBDUX driver where the ADC for example takes 800us to measure all data > so that a couple of zero length packets were generated until new data > has been created.
I assume you're talking about isoc-IN transfers where the device either sends a 0-length packet or doesn't send any packet at all. When that happens, the corresponding urb_iso_packet_descriptor structure will contain 0 for .actual_length and either 0 for .status (if a 0-length packet was received) or -EXDEV for .status (if no packet was received). Your driver can check these values in the URB's completion routine. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
