Date: Sun, 15 Aug 2010 17:11:56 +0200 From: Hans Petter Selasky <hselasky@c2i.net> To: freebsd-usb@freebsd.org Cc: freebsd-gnats-submit@freebsd.org, Paul Thornton <prt@prt.org> Subject: Re: usb/149675: uftdi doesn't react to break properly Message-ID: <201008151711.56278.hselasky@c2i.net> In-Reply-To: <201008151431.o7FEVKS0026529@www.freebsd.org>
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On Sunday 15 August 2010 16:31:20 Paul Thornton wrote: > >Number: 149675 > >Category: usb > >Synopsis: uftdi doesn't react to break properly > >Confidential: no > >Severity: non-critical > >Priority: medium > >Responsible: freebsd-usb > >State: open > >Quarter: > >Keywords: > >Date-Required: > >Class: sw-bug > >Submitter-Id: current-users > >Arrival-Date: Sun Aug 15 14:40:00 UTC 2010 > >Closed-Date: > >Last-Modified: > >Originator: Paul Thornton > >Release: 8.1-RELEASE > >Organization: > > >Environment: > FreeBSD base01.local 8.1-RELEASE FreeBSD 8.1-RELEASE #0: Sun Aug 15 > 09:38:55 UTC 2010 root@base01.local:/usr/src/sys/i386/compile/TEST2 > i386 > > The same issue is seen with GENERIC kernel > > >Description: > When setting the BRKINT and ~IGNBRK options on a handle where the > underlying hardware has an FTDI chipset driven by uftdi and ucom, the > break condition is not correctly acted upon. The underlying hardware is > an FTDI FT232BL chip. > > The expected behaviour is that the buffer be flushed on reception of a > break when BRKINT is used, however the driver appears to behave as if > BRKINT is clear, as an additional 0x00 byte is seen and the buffer isn't > flushed. > > FreeBSD 7.2 and 8.0 also exhibit the same behaviour. > > Using the same test program, and same USB hardware, Linux behaves as per > documentation and flushes the buffer on reception of the break when BRKINT > is set. > > >How-To-Repeat: > Connect two machines using ftdi-driven hardware. > > Send a break followed by some data A. Send another break, followed by some > data B. > > The correct response should be that on the receiver the buffer is flushed > by both breaks, and a read will only return the data B. > > What is likely to be read, however, is: 0x00 [A A A A A] 0x00 [B B B B B] > > The code I was using which brought this issue to light can be downloaded > from: http://www.prt.org/dmxrx2.c > Hi, Compile a kernel with "options USB_DEBUG". Enable FTDI debugging: sysctl hw.usb.uftdi.debug=15 Do you seen any debug prints when sending BREAK? --HPShelp
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