Apologies for the multiple send, I had an inbound mail problem. On Tue, Jan 10, 2017 at 8:53 AM, Greg KH <greg@xxxxxxxxx> wrote: > On Mon, Jan 09, 2017 at 10:24:42PM +0200, Rogan Dawes wrote: >> Sigh! This got bounced because of HTML parts. >> >> Another question that arises, though: >> >> What sort of performance can I expect writing to and reading from a >> RAW HID gadget, configured using that descriptor? >> >> My understanding is that I should be able to get 64kBps, based on a >> 64-byte packet, and a 1000 packet per second limit. > > Where do you get that per-second limit? > > It's up to the host to pull from the device that fast, perhaps it's not > really doing that? Using usbmon should show you what is going on here > exactly. > > thanks, > > greg k-h I got the idea that the per-second limit was 1000 from the LUFA stack, which has this as part of its descriptors: http://fourwalledcubicle.com/files/LUFA/Doc/151115/html/struct_u_s_b___descriptor___endpoint__t.html#a816d81c288de4e5779df22923e1ac0b7 uint8_t USB_Descriptor_Endpoint_t::PollingIntervalMS Polling interval in milliseconds for the endpoint if it is an INTERRUPT or ISOCHRONOUS type. So, apparently I'm clueless. Nonetheless, I have read reports of people getting 40kBps via raw HID, so it should be possible to do better than I am currently. I'll keep trying, and see if I can get proper packet traces on the bus to clarify what is going on. Regards, Rogan -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
