path: root/Documentation/sound/oss/VIA-chipset
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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /Documentation/sound/oss/VIA-chipset
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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+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
+#define isa_dma_bridge_buggy (0)
+#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.