Date: Fri, 3 May 2019 17:04:36 +0930 From: "O'Connor, Daniel" <darius@dons.net.au> To: Hans Petter Selasky <hps@selasky.org> Cc: freebsd-usb@freebsd.org Subject: Re: USB transfers in device drivers Message-ID: <832686F8-4E93-4039-8489-B48CB3B7B809@dons.net.au> In-Reply-To: <93e4ad37-bb57-b186-4743-d6ad86cd40ce@selasky.org> References: <3B922C60-32E5-484E-8AFA-28FF7255CF2C@dons.net.au> <af8dfb40-1d48-d03b-465f-32b4361e91c0@selasky.org> <D73B37BF-8C28-4EE4-8026-5E9BF8B5C4AD@dons.net.au> <e4fdb075-faa8-7832-227b-89700e832162@selasky.org> <BBA09A08-52F1-413F-861A-D607F91531C1@dons.net.au> <bda9e5c6-e5c0-10c2-c46b-801be66cac5f@selasky.org> <64924732-9848-4AF6-B37E-4ED3889DB711@dons.net.au> <0d155a73-31b1-d901-9874-6cb017e6b5d5@selasky.org> <612D5BA0-8580-4CA0-9D8F-67E7D60B2692@dons.net.au> <93e4ad37-bb57-b186-4743-d6ad86cd40ce@selasky.org>
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> On 3 May 2019, at 02:31, Hans Petter Selasky <hps@selasky.org> wrote: >=20 > On 2019-05-02 13:38, O'Connor, Daniel wrote: >>> On 2 May 2019, at 20:33, Hans Petter Selasky <hps@selasky.org> = wrote: >>>=20 >>> On 2019-05-02 12:44, O'Connor, Daniel wrote: >>>>> On 2 May 2019, at 20:02, Hans Petter Selasky <hps@selasky.org> = wrote: >>>>>=20 >>>>> On 2019-05-02 11:18, O'Connor, Daniel wrote: >>>>>> OK, thanks. >>>>>> To be honest I would much prefer to work out why this particular = hardware & software seem to drop the ball for such a long time - 50msec = without the kernel getting to schedule something (on a basically idle = system) is quite perplexing to me. >>>>>=20 >>>>> Sounds like a lost IRQ issue. Did you try any of the EHCI quirks = in hw.usb.ehci ? >>>> No not, yet - thanks for the pointer! >>>=20 >>> The 50ms delay may also be due to a physical link data error and = needed recovery through clear stall which is expensive. >>>=20 >> I see the same error on different hardware sets (both motherboard and = USB device) so I don't think it's that. >=20 > If you can check if a USB BULK transfer is pending during this delay, = then it might also be a firmware issue. OK, I'll try and come up with a program to process usbdump output and = show things like response latency. -- Daniel O'Connor "The nice thing about standards is that there are so many of them to choose from." -- Andrew Tanenbaum
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