Bezüglich Ian Lepore's Nachricht vom 17.09.2013 18:16 (localtime): > On Tue, 2013-09-17 at 17:38 +0200, Harald Schmalzbauer wrote: >> ... >>> Try this patch and see what happens: >>> >>> ================================================================== >>> --- umcs.c (revision 255492) >>> +++ umcs.c (local) >>> @@ -230,6 +230,7 @@ >>> .bufsize = 0, /* use wMaxPacketSize */ >>> .callback = &umcs7840_intr_callback, >>> .if_index = 0, >>> + .interval = 20, /* ms */ >>> }, >>> }; >>> >>> >>> BTW: I see that the umcs driver shouldn't do synchronous control >>> transfers from the USB interrupt transfer callback. This should be >>> postponed into some worker thread, for example the USB explore thread. >>> See USB audio driver for an example. >>> >>> --HPS >> I tried your patch and it works as expected: IRQs decreased to ~64/s >> when idle/disconnected. >> >> One interesting thing I never measured before: >> Console connection with 115k2 via umcs and 'while ( 2>1 ) echo "---..." >> end' results in 8000 irqs/s :-( But that's also true for the prolific >> (uplcom). The latter just goes down to 0.0 irqs/s when idle. >> >> Doing the same with uart0 results in 1444irqs/s. >> Is it by design/unavoidable that transfering the same via USB multiplies >> by factor 5-6? >> >> Thanks, >> >> -Harry >> > I don't know about that chipset, but with the FTDI chips it does xfers > in 64 byte chunks and high speed bulk data results in an astronomical > number of interrupts (and if you go fast enough, lost data). I have
According to ASIX product brief, MCS7840 has 512 byte buffer. Pretty much for an UART I think, which should make 115k2 baud connections with less than 30 transfers/s work, or am I missing something? > some patches that assemble lots of the little chip-size buffers into > bigger xfers that the ohci/ehci controller can handle without > interrupting the processor; that helps the problem a bunch. I think I also have at least one FTDI adapter arround, so I'd happily testing if I can make it compile on RELENG_9_2. Thanks, -Harry
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