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/* $XFree86: xc/programs/Xserver/hw/xfree86/os-support/sco/sco_iop.c,v 1.1 2002/06/03 21:22:10 dawes Exp $ */
/*
* Copyright 2001 by J. Kean Johnston <jkj@caldera.com>
*
* Permission to use, copy, modify, distribute, and sell this software and its
* documentation for any purpose is hereby granted without fee, provided that
* the above copyright notice appear in all copies and that both that
* copyright notice and this permission notice appear in supporting
* documentation, and that the name J. Kean Johnston not be used in
* advertising or publicity pertaining to distribution of the software without
* specific, written prior permission. J. Kean Johnston makes no
* representations about the suitability of this software for any purpose.
* It is provided "as is" without express or implied warranty.
*
* J. KEAN JOHNSTON DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
* EVENT SHALL J. KEAN JOHNSTON BE LIABLE FOR ANY SPECIAL, INDIRECT OR
* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
* USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
* OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
/* $XConsortium$ */
#include "X.h"
#include "compiler.h"
#define _NEED_SYSI86
#include "xf86.h"
#include "xf86Priv.h"
#include "xf86OSpriv.h"
#include "xf86_OSlib.h"
/***************************************************************************/
/* I/O Permissions section */
/***************************************************************************/
/*
* There is a right way and a wrong way of doing this. Unfortunately, we
* are forced to do it the wrong way. The right way is to be told the range
* or ranges of I/O ports the driver(s) need access to, in order to use the
* CONS_IOPERM ioctl() to grant access only to those ports we care about.
* This way we can guarantee some small level of stability because a driver
* does not have access to all ports (which would mean it could play with
* the PIT and thus affect scheduling times, or a whole slew of other
* nasty things). However, because XFree86 currently only enables or disables
* ALL port access, we need to run at IOPL 3, which basically means the
* X Server runs at the same level as the kernel. You can image why this is
* unsafe. Oh, and this is not a problem unique to OSR5, other OSes are
* affected by this as well.
*
* So, for the time being, we change our IOPL until such time as the XFree86
* architecture is changed to allow for tighter control of I/O ports. If and
* when it is, then the CONS_ADDIOP/DELIOP ioctl() should be used to enable
* or disable access to the desired ports.
*/
extern long sysi86 (int cmd, ...);
static Bool IOEnabled = FALSE;
void xf86EnableIO(void)
{
if (IOEnabled)
return;
if (sysi86(SI86V86, V86SC_IOPL, PS_IOPL) < 0)
FatalError("Failed to set IOPL for extended I/O\n");
IOEnabled = TRUE;
}
void xf86DisableIO(void)
{
if (!IOEnabled)
return;
sysi86(SI86V86, V86SC_IOPL, 0);
IOEnabled = FALSE;
}
/***************************************************************************/
/* Interrupt Handling section */
/***************************************************************************/
Bool xf86DisableInterrupts()
{
if (!IOEnabled) {
if (sysi86(SI86V86, V86SC_IOPL, PS_IOPL) < 0)
return FALSE;
}
#ifdef __GNUC__
__asm__ __volatile__("cli");
#else
asm("cli");
#endif /* __GNUC__ */
if (!IOEnabled) {
sysi86(SI86V86, V86SC_IOPL, PS_IOPL);
}
return(TRUE);
}
void xf86EnableInterrupts()
{
if (!IOEnabled) {
if (sysi86(SI86V86, V86SC_IOPL, PS_IOPL) < 0)
return;
}
#ifdef __GNUC__
__asm__ __volatile__("sti");
#else
asm("sti");
#endif /* __GNUC__ */
if (!IOEnabled) {
sysi86(SI86V86, V86SC_IOPL, PS_IOPL);
}
}
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