1Running sound cards on VIA chipsets
2
3o	There are problems with VIA chipsets and sound cards that appear to
4	lock the hardware solidly. Test programs under DOS have verified the
5	problem exists on at least some (but apparently not all) VIA boards
6
7o	VIA have so far failed to bother to answer support mail on the subject
8	so if you are a VIA engineer feeling aggrieved as you read this
9	document go chase your own people. If there is a workaround please
10	let us know so we can implement it.
11
12
13Certain patterns of ISA DMA access used for most PC sound cards cause the
14VIA chipsets to lock up. From the collected reports this appears to cover a
15wide range of boards. Some also lock up with sound cards under Win* as well.
16
17Linux implements a workaround providing your chipset is PCI and you compiled
18with PCI Quirks enabled. If so you will see a message
19	"Activating ISA DMA bug workarounds"
20
21during booting. If you have a VIA PCI chipset that hangs when you use the
22sound and is not generating this message even with PCI quirks enabled
23please report the information to the linux-kernel list (see REPORTING-BUGS).
24
25If you are one of the tiny number of unfortunates with a 486 ISA/VLB VIA
26chipset board you need to do the following to build a special kernel for
27your board
28
29	edit linux/include/asm-i386/dma.h
30
31change
32
33#define isa_dma_bridge_buggy 	(0)
34
35to
36
37#define isa_dma_bridge_buggy 	(1)
38
39and rebuild a kernel without PCI quirk support.
40
41
42Other than this particular glitch the VIA [M]VP* chipsets appear to work
43perfectly with Linux.
44