diff options
| author | msmith <msmith@FreeBSD.org> | 1997-07-28 07:49:40 +0000 |
|---|---|---|
| committer | msmith <msmith@FreeBSD.org> | 1997-07-28 07:49:40 +0000 |
| commit | a3e55966a073a41413c2b335a85d64c9d93c834f (patch) | |
| tree | dddd2e0c36ff6fd451a709a187844097cdcd0941 /sys/i386/isa/isa.c | |
| parent | d22bd4cd5ef12575b5db2ed91ad9b34848d90066 (diff) | |
| download | FreeBSD-src-a3e55966a073a41413c2b335a85d64c9d93c834f.zip FreeBSD-src-a3e55966a073a41413c2b335a85d64c9d93c834f.tar.gz | |
Use disable_intr() / read/write_eflags() to ensure that interrupt
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>
Diffstat (limited to 'sys/i386/isa/isa.c')
| -rw-r--r-- | sys/i386/isa/isa.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/sys/i386/isa/isa.c b/sys/i386/isa/isa.c index c51b59b..cc7f08d 100644 --- a/sys/i386/isa/isa.c +++ b/sys/i386/isa/isa.c @@ -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) { |
