On Fri, 28 Sep 2001, Jean Tourrilhes wrote: > Cleanup of the USB driver + the critical fix of last week.
Hi Jean, as you might have noticed, I'm using the ACT-IR2000U as FIR peer device to test the vlsi_ir driver. I have it connected to usb-ohci (SiS onboard chipset). When I saw your patch to add USB_ZERO_PACKET support for usb-ohci on linux-usb-devel recently, I was wondering why I never experienced any problem. I believe the reason is because with my tests it was pretty unlikely to hit the case where the zero-sized packet is required. With irlap-datasize 2048 the normal urb->transfer_length would be 2051 for example, due to the added irda-usb header and the irlap "A" and "C" fields. So my question is whether you could give me some pointer to special test cases which provide better coverage for paths like this, i.e. some way to control the raw packet size to test critical cases. Do you just use the MTU or some customized raw sockets? Another thing, I see some 8-10% gain in throughput when I completely disable the mtt-delay in the irda-usb driver. This should be ok, since irda-usb 1.0 spec requires the device to handle this by itself. My ACT-IR200U Rev 1.00 apparently does this well. So I'm wondering whether there are other devices requiring this or I might simply not have hit the case where it breaks (yes, I know, all the irda-usb dongles seem to violate the spec, at least wrt. when to apply speed changes...). However, I have not analyzed the USB traffic - chances are the 1 msec mtt-delay (sufficient for the OB800) is always achieved due to USB latencies, when the newly submitted URB will not be processed before the next USB frame starts. Comments? Martin _______________________________________________ Linux-IrDA mailing list - [EMAIL PROTECTED] http://www.pasta.cs.UiT.No/mailman/listinfo/linux-irda
