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Use disable_intr() / read/write_eflags() to ensure that interrupt

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handlers don't skew the results of isa_dmastatus.  The function can be
safely called with interrupts disabled.

Submitted by:	Stephen McKay <syssgm@dtir.qld.gov.au>
This commit is contained in:
Mike Smith 1997-07-28 07:49:40 +00:00
parent 053f348568
commit 53f83ec34c
2 changed files with 12 additions and 8 deletions
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10
sys/amd64/isa/isa.c
View File

@ -34,7 +34,7 @@
* SUCH DAMAGE.
*
* from: @(#)isa.c 7.2 (Berkeley) 5/13/91
* $Id: isa.c,v 1.95 1997/07/20 14:10:03 bde Exp $
* $Id: isa.c,v 1.96 1997/07/24 05:27:39 msmith Exp $
*/
/*
@ -905,8 +905,9 @@ int
isa_dmastatus(int chan)
{
u_long cnt = 0;
int ffport, waport, s;
int ffport, waport;
u_long low, high, low2, high2;
u_long ef;
/* channel active? */
if (dma_inuse & (1 << chan) == 0) {
@ -927,14 +928,15 @@ isa_dmastatus(int chan)
waport = DMA2_CHN(chan - 4) + 2;
}
s = splhigh(); /* no interrupts Mr Jones! */
ef = read_eflags(); /* get current flags */
disable_intr(); /* no interrupts Mr Jones! */
outb(ffport, 0); /* clear register LSB flipflop */
low = inb(waport);
high = inb(waport);
outb(ffport, 0); /* clear again (paranoia?) */
low2 = inb(waport);
high2 = inb(waport);
splx(s);
write_eflags(ef); /* restore flags */
/* now decide if a wrap has tried to skew our results */
if (low >= low2) {

10
sys/i386/isa/isa.c
View File

@ -34,7 +34,7 @@
* SUCH DAMAGE.
*
* from: @(#)isa.c 7.2 (Berkeley) 5/13/91
* $Id: isa.c,v 1.95 1997/07/20 14:10:03 bde Exp $
* $Id: isa.c,v 1.96 1997/07/24 05:27:39 msmith Exp $
*/
/*
@ -905,8 +905,9 @@ int
isa_dmastatus(int chan)
{
u_long cnt = 0;
int ffport, waport, s;
int ffport, waport;
u_long low, high, low2, high2;
u_long ef;
/* channel active? */
if (dma_inuse & (1 << chan) == 0) {
@ -927,14 +928,15 @@ isa_dmastatus(int chan)
waport = DMA2_CHN(chan - 4) + 2;
}
s = splhigh(); /* no interrupts Mr Jones! */
ef = read_eflags(); /* get current flags */
disable_intr(); /* no interrupts Mr Jones! */
outb(ffport, 0); /* clear register LSB flipflop */
low = inb(waport);
high = inb(waport);
outb(ffport, 0); /* clear again (paranoia?) */
low2 = inb(waport);
high2 = inb(waport);
splx(s);
write_eflags(ef); /* restore flags */
/* now decide if a wrap has tried to skew our results */
if (low >= low2) {