HYPER-V(4)						   BSD Kernel Interfaces Manual 						HYPER-V(4)

NAME

     hv_ata_pci_disengage -- Hyper-V ATA PCI Disengage driver

SYNOPSIS

     To compile this driver into the kernel, place the following lines in the system kernel configuration file:

	   device hyperv

DESCRIPTION

     The hv_ata_pci_disengage driver prevents the native FreeBSD ATA driver from loading in the presence of Hyper-V.  FreeBSD guests running on
     Hyper-V can take advantage of the Hyper-V Storage Virtual Consumer (hv_storvsc(4)) for using their IDE devices.  Since the ATA driver serves
     IDE devices as well, there is a chance that the ATA driver may interfere with the operations of hv_storvsc(4).  The hv_ata_pci_disengage
     driver avoids conflicts between the ATA driver and hv_storvsc(4) by disabling the ATA driver when the FreeBSD guest is booting.

     A side effect of disabling the ATA driver is that CDROM may become inoperational on FreeBSD guest partitions.  If CDROM access is a must then
     users may use "set hw.ata.disk_enable=1" at boot time to prevent the ATA driver from being disabled.

SEE ALSO

     hv_netvsc(4), hv_storvsc(4), hv_utils(4), hv_vmbus(4)

HISTORY

     Support for hv_ata_pci_disengage first appeared in FreeBSD 10.0.  The driver was developed through a joint effort between Citrix Incorpo-
     rated, Microsoft Corporation, and Network Appliance Incorporated.

AUTHORS

     FreeBSD support for hv_ata_pci_disengage was first added by Microsoft BSD Integration Services Team <bsdic@microsoft.com>.

BSD
								September 10, 2013							       BSD