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author | peter <peter@FreeBSD.org> | 2004-08-16 22:51:13 +0000 |
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committer | peter <peter@FreeBSD.org> | 2004-08-16 22:51:13 +0000 |
commit | 2800cddd5fac766f4fafb2bff990cf4ad0f6a559 (patch) | |
tree | 937796fa4fa0eb301f41e5a49360a0f9b5972cf4 /sys/amd64/isa/isa_dma.c | |
parent | efc85186f06a07dcadd5d6e69cdfe77a2a3e3398 (diff) | |
download | FreeBSD-src-2800cddd5fac766f4fafb2bff990cf4ad0f6a559.zip FreeBSD-src-2800cddd5fac766f4fafb2bff990cf4ad0f6a559.tar.gz |
Sync with i386
Diffstat (limited to 'sys/amd64/isa/isa_dma.c')
-rw-r--r-- | sys/amd64/isa/isa_dma.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/sys/amd64/isa/isa_dma.c b/sys/amd64/isa/isa_dma.c index b6400dd..2017158 100644 --- a/sys/amd64/isa/isa_dma.c +++ b/sys/amd64/isa/isa_dma.c @@ -103,12 +103,20 @@ isa_dmainit(chan, bouncebufsize) { void *buf; + /* + * If a DMA channel is shared, both drivers have to call isa_dmainit + * since they don't know that the other driver will do it. + * Just return if we're already set up good. + * XXX: this only works if they agree on the bouncebuf size. This + * XXX: is typically the case since they are multiple instances of + * XXX: the same driver. + */ + if (dma_bouncebuf[chan] != NULL) + return; + #ifdef DIAGNOSTIC if (chan & ~VALID_DMA_MASK) panic("isa_dmainit: channel out of range"); - - if (dma_bouncebuf[chan] != NULL) - panic("isa_dmainit: impossible request"); #endif dma_bouncebufsize[chan] = bouncebufsize; |