How to do hardware DTR/DSR flow control on Linux (serial port programming)?

Question

How do I get the play head to consecutively go through the timeline containing objects in 4 frames on the click of a button using actionscript 3

Solution

Answering my own question, thanks to an hint from @ktf, I found out that at least since 2.6.28 [1] there are IOCTLs (TCGETX, TCSETX, TCSETXF & TCSETXW) to setup extended attributes.

They seem to have been added to the upstream kernel on 13 Oct 2008 [2].

These extra IOCTLs (compatible with SYS5) allow to configure each of the extra pins handling individually.

See the link for the original RHEL patch [3] and look on the attached test case for an example of how to use it.

The IOCTL definitions are on the "asm-generic/ioctls.h" file and the structure and flag constants are defined on "linux/termios.h" (in "/usr/include", off course).

UPDATE

Further research shows that the generic serial support for this IOCTL wasn't merged into the upstream kernel source. RHEL 5.3 has it, but not the upstream 3.0.6 kernel.
That means the ioctl() call will fail for any other kernel that didn't port the RHEL patch [4].

[1] http://lxr.free-electrons.com/ident?v=2.6.28;i=TCGETX
[2] https://lkml.org/lkml/2008/10/13/120
[3] https://bugzilla.redhat.com/show_bug.cgi?id=445211
[4] https://bugzilla.redhat.com/attachment.cgi?id=315300&action=diff

Comments

[Admin]

Voted to delete my answer to increase the chances of getting better answers. This really seems to be an interesting problem other people have faced, too. Interestingly there were at least 3 kernel patches (2001, 2008 and 2010) to address this issue, but none of them seem to be implemented in current ditribution kernels. Looks like only solution (if not taking the custom cable option) would be to patch the kernel on your own. If it's for POS terminals where you have control over all installes software, a BSD UNIX could also worth a try.

[Admin]

This comment actually helped me. I found that Red Hat Enterprise Linux 5.3 included a patch to fix this problem [1] on a 2.6.18 kernel. Since RHEL is pretty much a kind of industry standard I believe it's pretty safe to use their patch [2]. [1] rhn.redhat.com/errata/RHSA-2009-0225.html [2] bugzilla.redhat.com/show_bug.cgi?id=445211

[SoloWalker]

Okay, that's helpful but how do I get it to loop as in go back to first frame and continue

[Amy Blankenship]

Compare currentFrame to totalFrames. If you're on the last frame, gotoAndStop(1)