Date: Sat, 11 Jun 2011 17:43:11 -0400 (EDT) From: Charles Sprickman <spork@bway.net> To: freebsd-usb@freebsd.org Subject: ucom/uftdi high interrupt load Message-ID: <alpine.OSX.2.00.1106111715580.99056@hotlap.nat.fasttrackmonkey.com>
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Hello, We ran into an odd problem last week with our serial consoles after moving the USB to serial adapters from an old 4.11 box to a box running 8.1. We have two boxes that incorporate (I assume) hubs and a bunch of FTDI serial interfaces. One has 16 ports, the other 8. Each is plugged directly into a USB port on the rear of the mainboard. We run conserver[1] to handle access to the serial ports. From what I've observed, this application opens the ports when the daemon starts - it logs any output (handy for panics, or anything else that might spit interesting info to the console) and waits for clients to connect to it. Everything had been working fine for a few weeks. The box was rebooted recently to enable PostgreSQL to start normally (bumped SHM stuff in loader.conf). After six days, we found that the consoles were unresponsive. Restarting conserver brought us this each time we connected to a console for full read/write access: [Thu Jun 9 10:04:59 2011] conserver (50113): ERROR: [h22] open(/dev/ttyU4): Interrupted system call: forcing down [Thu Jun 9 10:04:59 2011] conserver (50112): ERROR: [h21] open(/dev/ttyU11): Interrupted system call: forcing down All devices still appeared in /dev. Stopping conserver and confirming it and all child processes were gone and then using picocom and cu yielded no response on the serial ports. We also found (after the fact) that around the time the consoles became unresponsive, cpu usage went to nearly 90% and was mostly in the kernel process "intr": root 12 70.5 0.0 0 136 ?? WL Fri12AM 120:01.47 [intr] A graph showing cpu usage (red is "system"): http://i.imgur.com/0yO5l.png I should note that we know the cpu spike and devices becoming unresponsive can be correlated because one of the serial ports runs a temperature monitor which is tied into our monitoring. When the data goes stale, we get notified. Issuing a "usbconfig -u 0 reset" caused all devices except for the root hub to disappear and not come back. CPU usage also dipped a bit after that. Rebooting was the only way to resolve the issue - perhaps plugging and unplugging would have worked, but that's a bit too complex for our remote hands. I can supply full dmesg and more, but for now, here's a summary of the usb info from dmesg: FreeBSD 8.1-RELEASE #7: Wed Dec 22 00:49:50 EST 2010 ohci0: <OHCI (generic) USB controller> mem 0xfe9fc000-0xfe9fcfff irq 10 at device 15.2 on pci0 ohci0: [ITHREAD] ... usbus0: <OHCI (generic) USB controller> on ohci0 usbus0: 12Mbps Full Speed USB v1.0 ugen0.1: <(0x1166)> at usbus0 ... uhub0: <(0x1166) OHCI root HUB, class 9/0, rev 1.00/1.00, addr 1> on usbus0 uhub0: 4 ports with 4 removable, self powered ugen0.2: <vendor 0x05e3> at usbus0 uhub1: <vendor 0x05e3 USB Hub, class 9/0, rev 1.01/0.11, addr 2> on usbus0 uhub1: 7 ports with 7 removable, self powered ugen0.3: <FTDI> at usbus0 uftdi0: <USB FAST SERIAL ADAPTER> on usbus0 uftdi1: <USB FAST SERIAL ADAPTER> on usbus0 ugen0.4: <FTDI> at usbus0 uftdi2: <USB FAST SERIAL ADAPTER> on usbus0 uftdi3: <USB FAST SERIAL ADAPTER> on usbus0 ugen0.5: <FTDI> at usbus0 uftdi4: <USB FAST SERIAL ADAPTER> on usbus0 uftdi5: <USB FAST SERIAL ADAPTER> on usbus0 ugen0.6: <FTDI> at usbus0 uftdi6: <USB FAST SERIAL ADAPTER> on usbus0 uftdi7: <USB FAST SERIAL ADAPTER> on usbus0 ugen0.7: <FTDI> at usbus0 uftdi8: <USB FAST SERIAL ADAPTER> on usbus0 uftdi9: <USB FAST SERIAL ADAPTER> on usbus0 ugen0.8: <FTDI> at usbus0 uftdi10: <USB FAST SERIAL ADAPTER> on usbus0 uftdi11: <USB FAST SERIAL ADAPTER> on usbus0 ugen0.9: <vendor 0x05e3> at usbus0 uhub2: <vendor 0x05e3 USB Hub, class 9/0, rev 1.01/0.12, addr 9> on usbus0 uhub2: 4 ports with 4 removable, self powered ugen0.10: <FTDI> at usbus0 uftdi12: <USB FAST SERIAL ADAPTER> on usbus0 uftdi13: <USB FAST SERIAL ADAPTER> on usbus0 ugen0.11: <FTDI> at usbus0 ... (mangling below is as it appears in dmesg) da1 at sym0 bus 0 scbus0 target 1 lun 0uftdi14: <USB FAST SERIAL ADAPTER> on usbus0 da1: <SEAGATE ST336807LW 0C01> Fixed Direct Access SCSI-3 device uftdi15: <USB FAST SERIAL ADAPTER> on usbus0 ... Root mount waiting for: usbus0 ugen0.12: <vendor 0x0409> at usbus0 uhub3: <vendor 0x0409 product 0x0050, class 9/0, rev 2.00/1.00, addr 12> on usbus0 Root mount waiting for: usbus0 uhub3: 7 ports with 7 removable, self powered ugen0.13: <FTDI> at usbus0 uftdi16: <FT232R USB UART> on usbus0 Root mount waiting for: usbus0 ugen0.14: <FTDI> at usbus0 uftdi17: <FT232R USB UART> on usbus0 Root mount waiting for: usbus0 ugen0.15: <FTDI> at usbus0 uftdi18: <FT232R USB UART> on usbus0 ugen0.16: <FTDI> at usbus0Root mount waiting for: usbus0 uftdi19: <FT232R USB UART> on usbus0 ugen0.17: <FTDI> at usbus0 uftdi20: <FT232R USB UART> on usbus0 Root mount waiting for: usbus0 ugen0.18: <FTDI> at usbus0 uftdi21: <FT232R USB UART> on usbus0 Root mount waiting for: usbus0 ugen0.19: <vendor 0x0409> at usbus0 uhub4: <vendor 0x0409 product 0x005a, class 9/0, rev 2.00/1.00, addr 19> on usbus0 uhub4: 4 ports with 4 removable, self powered Root mount waiting for: usbus0 ugen0.20: <FTDI> at usbus0 uftdi22: <FT232R USB UART> on usbus0 Root mount waiting for: usbus0 ugen0.21: <FTDI> at usbus0 uftdi23: <FT232R USB UART> on usbus0 Trying to mount root from zfs:zroot Thanks, Charles [1] - http://www.conserver.com/help
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