PCIIDE(4)

NAME
PCIIDE - PCI IDE disk controllers driver

SYNOPSIS
pciide* at pci? dev ? function ? flags 0x0000
options PCIIDE_CMD064x_DISABLE
options PCIIDE_AMD756_ENABLEDMA
options PCIIDE_CMD0646U_ENABLEUDMA

DESCRIPTION
The pciide driver supports the PCI IDE controllers as specified in the "PCI IDE controller specification, revision 1.0" draft, and provides the core functions for the wd and atapi drivers. This driver include specific, enhanced support for the CMD Tech PCI0640 controller, and IDE DMA/Ultra-DMA support for the following controllers:
-   Acer labs M5229 IDE Controller
-   Advanced Micro Devices AMD-756 IDE Controllers
-   CMD Tech PCI0643, PCI0646, PCI0648 and PCI0649 IDE Controllers
-   Contaq Microsystems/Cypress CY82C693 IDE Controller
-   HighPoint HPT366 Ultra/66 and HPT370 Ultra/100 (in Ultra/66 mode) IDE controller
-   Intel PIIX, PIIX3 and PIIX4 IDE Controllers
-   Intel 82801 (ICH/ICH0) IDE Controllers
-   OPTi 82c621 (plus a few of its derivatives) IDE Controllers
-   Promise PDC20246 (Ultra/33), PDC20262 (Ultra/66), and Ultra100 (in Ultra/66 mode only) PCI IDE controllers
-   Silicon Integrated System 5597/5598 IDE controller
-   VIA Technologies VT82C586 and VT82C586A IDE Controllers
Some of these controllers are only available in multifunction PCI chips.

The 0x0001 flag forces the PCIIDE driver to use DMA when there is no explicit DMA mode setting support for the controller but DMA is present. If the BIOS didn't set up the controller properly, this can cause a machine hang.

BUGS
There's no way to reliably know if a PCI064x controller is enabled or not. If the driver finds a PCI064x, it will assume it is enabled unless the PCIIDE_CMD064x_DISABLE option is specified in the kernel config file. This will be a problem only if the controller has been disabled in the BIOS and another controller has been installed and uses the ISA legacy I/O ports and interrupts.

The PCI0646U controller is known to be buggy with Ultra-DMA transfers, so Ultra-DMA is disabled by default for this controller. To enable Ultra-DMA, use the PCIIDE_CMD0646U_ENABLEUDMA option. Ultra-DMA can eventually be disabled on a per-drive basis with config flags, see wd(4).

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 (except the OPTi controller, which supports both 25 and 33 Mhz PCI bus timings). This driver may not work properly on overclocked systems.

SEE ALSO
intro(4), pci(4), scsi(4), wd(4), wdc(4)