wd(4) [netbsd man page]

WD(4)							   BSD Kernel Interfaces Manual 						     WD(4)

NAME

     wd -- WD100x compatible hard disk driver

SYNOPSIS

     wd* at atabus? drive ? flags 0x0000
     wd* at umass?
     options WD_SOFTBADSECT

DESCRIPTION

     The wd driver supports hard disks that emulate the Western Digital WD100x.  This includes standard MFM, RLL, ESDI, IDE, EIDE, and SATA
     drives.

     The flags are used only with controllers that support DMA operations and mode settings (like some pciide controllers).  The lowest order nib-
     ble (rightmost digit) of the flags defines the PIO mode, the next four bits define the DMA mode and the third nibble defines the UltraDMA
     mode.  For each set of four bits, the 3 lower bits define the mode to use and the last bit must be set to 1 for this setting to be used.  For
     DMA and UDMA, 0xf (1111) means 'disable'.	For example, a flags value of 0x0fac (1111 1010 1100) means 'use PIO mode 4, DMA mode 2, disable
     UltraDMA'.  0x0000 means "use whatever the drive claims to support."

     The kernel configuration option ``options WD_SOFTBADSECT'' enables a software managed bad-sector list which will prevent further accesses to
     sectors where an unrecoverable read error occurred.  A user interface is provided by dkctl(8).  Unlike the (historical) mechanisms provided
     by bad144(8) and badsect(8) the software list does neither support sector replacement nor is it saved across reboots.

SEE ALSO

     ata(4), intro(4), pciide(4), scsi(4), umass(4), wdc(4), atactl(8), dkctl(8)

BUGS

     The optional software bad sector list does not interoperate well with sector remapping features of modern disks.  To let the disk remap a
     sector internally, the software bad sector list must be flushed or disabled before.

BSD
								  August 30, 2004							       BSD

VIAIDE(4)						   BSD 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, 768 and CS5536 IDE Controllers
	   -   NVIDIA nForce, nForce2, nForce2 400, nForce3, nForce3 250, nForce4, MCP04, MCP55, MCP61, MCP65, MCP67 IDE and SATA Controllers.
	   -   VIA Technologies VT82C586, VT82C586A, VT82C596A, VT82C686A, VT8233A, VT8235, VT8237/VT8237R IDE Controllers, VT6421 Serial RAID
	       Controller and CX700 IDE Controller.

     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)

NOTES

     Drives on the VT6421 Serial RAID Controller can only be accessed after they have been configured into RAID or JBOD sets via its BIOS.  It is
     also inaptly named as it has both SATA and PATA interfaces.

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 necessary 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.

BSD
								  August 31, 2007							       BSD