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<== Date ==> | <== Thread ==> |
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Subject: | Access to IO registers from user-space in recent Linux versions |
From: | "Mark Rivers" <[email protected]> |
To: | "tech-talk" <[email protected]>, <[email protected]> |
Date: | Thu, 9 Jul 2009 13:08:06 -0500 |
Folks, I have an EPICS application
that directly accesses the parallel port (EPP) registers from user space on
Linux. This is to communicate with an XIA Saturn spectroscopy module. In order versions of Linux
this worked fine if I ran the application as root, or by calling iopl(3) as
root before exec-ing the EPICS application. I am now trying to run this
under a recent Linux (Redhat Fedora) version baja:~>more /proc/version Linux version
2.6.26.8-57.fc8 ([email protected]) (gcc version 4.1.2 20070925
(Red Hat 4.1.2-33)) #1 SMP Thu Dec 18 18:59:49
EST 2008 The EPICS IOC now crashes
with a segmentation fault when trying to access the EPP port, even when running
as root, and the following entry appears in /var/log/messages Jul 9 11:43:44 baja
kernel: dxpApp[27837] general protection ip:80a90a6 sp:ff8ea8ac error:0 in dxpApp[8048000+1f7000] Does anyone know what one
needs to do in recent Linux versions to get access to the IO registers from
user-space? Thanks, Mark |