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Diffstat (limited to 'Documentation/sound/oss/VIA-chipset')
-rw-r--r-- | Documentation/sound/oss/VIA-chipset | 43 |
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diff --git a/Documentation/sound/oss/VIA-chipset b/Documentation/sound/oss/VIA-chipset new file mode 100644 index 0000000..3786523 --- /dev/null +++ b/Documentation/sound/oss/VIA-chipset @@ -0,0 +1,43 @@ +Running sound cards on VIA chipsets + +o There are problems with VIA chipsets and sound cards that appear to + lock the hardware solidly. Test programs under DOS have verified the + problem exists on at least some (but apparently not all) VIA boards + +o VIA have so far failed to bother to answer support mail on the subject + so if you are a VIA engineer feeling aggrieved as you read this + document go chase your own people. If there is a workaround please + let us know so we can implement it. + + +Certain patterns of ISA DMA access used for most PC sound cards cause the +VIA chipsets to lock up. From the collected reports this appears to cover a +wide range of boards. Some also lock up with sound cards under Win* as well. + +Linux implements a workaround providing your chipset is PCI and you compiled +with PCI Quirks enabled. If so you will see a message + "Activating ISA DMA bug workarounds" + +during booting. If you have a VIA PCI chipset that hangs when you use the +sound and is not generating this message even with PCI quirks enabled +please report the information to the linux-kernel list (see REPORTING-BUGS). + +If you are one of the tiny number of unfortunates with a 486 ISA/VLB VIA +chipset board you need to do the following to build a special kernel for +your board + + edit linux/include/asm-i386/dma.h + +change + +#define isa_dma_bridge_buggy (0) + +to + +#define isa_dma_bridge_buggy (1) + +and rebuild a kernel without PCI quirk support. + + +Other than this particular glitch the VIA [M]VP* chipsets appear to work +perfectly with Linux. |