Experimental Physics and
Industrial Control System
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| <== Date ==> | <== Thread ==> |
|---|
| Subject: | Re: Linux and EPICS threads |
| From: | Eric Norum <[email protected]> |
| To: | Mark Rivers <[email protected]> |
| Cc: | [email protected] |
| Date: | Wed, 30 Jul 2003 12:49:13 -0500 |
Andrew Johnson wrote:
You will need to worry about more than one thread - each different scan period has its own thread, so it just takes the user
changing
the SCAN field of the record for your code to have to call iopl(3) yet
again, and if it's set to Process Passive then there are several other
tasks that might be used depending on how the processing is initiated.
Actually, it's not that bad in my case. All of the actual I/O is done by an MPF server task. Device support just sends messages to the MPF server, so the tasks that process the record do not need iopl() privilege.
I've got it working by calling iopl() in the MPF server task initialization. It's not as clean as I'd like, because it requires some #ifdef linux code, but it's OK.
I'd recommend calling ioperm() rather than iopl() since ioperm opens only a specified window into the inp/outp space so you can't accidentally tromp on some other (critical) port.
-- Eric Norum [email protected] Advanced Photon Source Phone: (630) 252-4793 Argonne National Laboratory
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- RE: Linux and EPICS threads John Quintana
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- RE: Linux and EPICS threads Mark Rivers
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