*BSD News Article 8156


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From: roell@informatik.tu-muenchen.de (Thomas Roell)
Subject: Re: I need 8514/ATI Graphics Ultra support for ISC UNIX SVR3.2 & X11R4
In-Reply-To: curtis@cs.berkeley.edu's message of 25 Nov 1992 06:08:50 GMT
References: <1992Nov23.073800.6592@Informatik.TU-Muenchen.DE>
	<1eshe9INNeum@agate.berkeley.edu>
	<1992Nov24.172506.29957@Informatik.TU-Muenchen.DE>
	<1ev59iINNt8v@agate.berkeley.edu>
Sender: news@Informatik.TU-Muenchen.DE (USENET Newssystem)
Organization: Inst. fuer Informatik, Technische Univ. Muenchen, Germany
Date: Thu, 26 Nov 1992 08:44:26 GMT
Message-ID: <1992Nov26.084426.6042@Informatik.TU-Muenchen.DE>
Lines: 33

>|>Roell has, in the past, claimed that SysV use of X8514 requires kernel
>|>mods; this is also false.  SVR3 has a call to enable user-level port
>|>access, and I believe SVR4 has it too.
>|
>|Yes, both SVR3.2 and SVR4 have calls to enable generall io port access
>|priviege:
>|
>|  sysi86(SI86V86, V86SC_IOPL, PS_IOPL);
>|
>|That's not the problem. The problem is that some unixes are buggy to
>|keep this privilege. That has to do with the mechanisms how the
>|kernels restores the user context after a signal has been processed in
>|user space. ISC 2.0.2 has this problem, while 2.2 and 3.x doesn't.
>|Also some older SVR4s (4.0.1 and 4.0.2) have this problem.
>
>Just be careful not to send your X server any signals :-)

Well, that's the big problem. xinit for example sends the server a
signal to terminate ... The xque which some SVR4s have to use for
mouse and keyboard input works with signals. And I believe some other
functions in libsocket.so might use alarm(2) which would cause a
signal, too. Also what about SIGIO ?

- Thomas




--
-------------------------------------------------------------------------------
Das Reh springt hoch, 				e-mail: roell@sgcs.com
das Reh springt weit,				#include <sys/pizza.h>
was soll es tun, es hat ja Zeit ...