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.Dd September 10, 2013 .Dt HYPER-V 4 .Os .Sh NAME .Nm hv_ata_pci_disengage .Nd Hyper-V ATA PCI Disengage driver .Sh SYNOPSIS To compile this driver into the kernel, place the following lines in the system kernel configuration file: d -ragged -offset indent .Cd "device hyperv" .Ed .Sh DESCRIPTION The .Nm driver prevents the native .Fx ATA driver from loading in the presence of Hyper-V. .Fx guests running on Hyper-V can take advantage of the Hyper-V Storage Virtual Consumer
q Xr 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 .Xr hv_storvsc 4 . The .Nm driver avoids conflicts between the ATA driver and .Xr hv_storvsc 4 by disabling the ATA driver when the .Fx guest is booting.
p A side effect of disabling the ATA driver is that CDROM may become inoperational on .Fx 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. .Sh SEE ALSO .Xr hv_netvsc 4 , .Xr hv_storvsc 4 , .Xr hv_utils 4 , .Xr hv_vmbus 4 .Sh HISTORY Support for .Nm first appeared in .Fx 10.0 . The driver was developed through a joint effort between Citrix Incorporated, Microsoft Corporation, and Network Appliance Incorporated. .Sh AUTHORS .An -nosplit .Fx support for .Nm was first added by .An Microsoft BSD Integration Services Team Aq Mt bsdic@microsoft.com .