Date: Mon, 23 Dec 1996 03:50:01 -0800 (PST) From: Bruce Evans <bde@zeta.org.au> To: freebsd-bugs Subject: Re: kern/2270: Hayes ESP serial card locks system as of 12/01 kernel. Message-ID: <199612231150.DAA00134@freefall.freebsd.org>
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The following reply was made to PR kern/2270; it has been noted by GNATS. From: Bruce Evans <bde@zeta.org.au> To: freebsd-gnats-submit@freebsd.org, george@cia-g.com Cc: Subject: Re: kern/2270: Hayes ESP serial card locks system as of 12/01 kernel. Date: Mon, 23 Dec 1996 22:43:24 +1100 >>Description: >Accessing the serial port device for the Hayes ESP card, /dev/cuaa2, >the system completely locks up and forced to reset. >>How-To-Repeat: >When the line "modem d a 2" in rc.serial is run at start up, the >system locks up tight. Commenting out that line and after the >system completly boots, running "cu -l /dev/cuaa2" also causes the >system to completly lock up. Someone else reported that there is a problem with the ESP only(?) when the port is closed. >This is happening with all the kernels I've compiled using the >kernel sources after and including 12/01, "cvs update -D 12/01/1996". >The kernel of 11/30 apparently works fine. The sio driver now assumes that the Transmitter Holding Register Empty (THRE) bit works normally in more cases. If it doesn't work, then sioclose() might hang if there is output in progress. The system shouldn't hang, but if the hang is during early execution of rc.serial, then it would be hard to tell the difference. Try setting a timeout of N seconds using `comcontrol /dev/cuaa2 drainwait N' very early (before anything else in rc.serial). I'm not sure if this is the problem - /etc/rc.serial shouldn't generate any output. If it is, then THRE might fail because the UART is doing flow control that the driver doesn't know about. Bruce
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