misc/144696: tcdrain(3) does not work right with uart(4) driver
Uniballer
nobody at igetenoughspamthanku.org
Fri Mar 12 15:20:02 UTC 2010
>Number: 144696
>Category: misc
>Synopsis: tcdrain(3) does not work right with uart(4) driver
>Confidential: no
>Severity: serious
>Priority: high
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Fri Mar 12 15:20:01 UTC 2010
>Closed-Date:
>Last-Modified:
>Originator: Uniballer
>Release: 8.0-RELEASE-p2
>Organization:
>Environment:
FreeBSD ????.xxxx.com 8.0-RELEASE-p2 FreeBSD 8.0-RELEASE-p2 #0: Tue Jan 5 16:02:27 UTC 2010 root at i386-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC i386
>Description:
tcdrain(3) does not wait for serial output to complete when used with the uart(4) driver. This worked correctly on 6.4 and 7.x with the sio(4) driver.
>How-To-Repeat:
Loop back a serial port, write a long buffer to it, then call tcdrain(3) to wait for output to complete, and call tcflush(3) to get rid of the data. A subsequent read will show that part of the data is in the receive buffer, probably because it was received after tcflush(3) was called because tcdrain(3) was called early.
See http://forums.freebsd.org/showthread.php?t=12154 for more info and sample code.
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted:
More information about the freebsd-bugs
mailing list