viaide(4) - NetBSD Manual Pages

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VIAIDE(4)               NetBSD Kernel Interfaces Manual              VIAIDE(4)


NAME

     viaide - AMD, NVIDIA and VIA IDE disk controllers driver


SYNOPSIS

     viaide* at pci? dev ? function ? flags 0x0000
     options PCIIDE_AMD756_ENABLEDMA


DESCRIPTION

     The viaide driver supports the following IDE controllers and provides the
     interface with the hardware for the ata driver:
           -   Advanced Micro Devices AMD-756, 766, and 768 IDE Controllers
           -   NVIDIA nForce and nForce2
           -   VIA Technologies VT82C586, VT82C586A, VT82C596A, VT82C686A,
               VT8233A, VT8235 and VT8237 IDE Controllers

     The 0x0002 flag forces the viaide driver to disable DMA on chipsets for
     which DMA would normally be enabled.  This can be used as a debugging
     aid, or to work around problems where the IDE controller is wired up to
     the system incorrectly.


SEE ALSO

     ata(4), atapi(4), intro(4), pci(4), pciide(4), wd(4), wdc(4)


BUGS

     The AMD756 chip revision D2 has a bug affecting DMA (but not Ultra-DMA)
     modes.  The workaround documented by AMD is to not use DMA on any drive
     which does not support Ultra-DMA modes.  This does not appear to be nec-
     essary on all drives, the PCIIDE_AMD756_ENABLEDMA option can be used to
     force multiword DMA on the buggy revisions.  Multiword DMA can eventually
     be disabled on a per-drive basis with config flags, see wd(4).  The bug,
     if triggered, will cause a total system hang.

     The timings used for the PIO and DMA modes for controllers listed above
     are for a PCI bus running at 30 or 33 MHz.  This driver may not work
     properly on overclocked systems.

NetBSD 2.0.2                    October 8, 2003                   NetBSD 2.0.2