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Document new hint.atapci.X.msi and hint.ata.X.pm_level tunables.

This commit is contained in:
Alexander Motin 2009-06-24 19:25:47 +00:00
parent 7af55bd450
commit f64d65b27e
Notes: svn2git 2020-12-20 02:59:44 +00:00
svn path=/head/; revision=194890

View File

@ -27,7 +27,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd October 4, 2008
.Dd June 24, 2009
.Dt ATA 4
.Os
.Sh NAME
@ -93,6 +93,24 @@ set to 1 for DMA access, 0 for PIO (default is DMA).
set to 1 to enable Write Caching, 0 to disable (default is enabled).
.Em WARNING :
can cause data loss on power failures and crashes.
.It Va hint.atapci.X.msi
set to 1 to allow Message Signalled Interrupts (MSI) to be used by
specified PCI ATA controller, if supported.
.It Va hint.ata.X.pm_level
controls SATA interface Power Management for specified channel,
allowing to save some power by the cost of additional command latency.
Possible values:
.Bl -tag -compact
.It 0
interface Power Management is disabled, default value.
.It 1
device is allowed to initiate PM state change, host is passive.
.It 2
host initiates PARTIAL PM state transition every time port becomes idle.
.It 3
host initiates SLUMBER PM state transition every time port becomes idle.
.El
Modes 2 and 3 are implemented only for AHCI driver now.
.El
.Sh DESCRIPTION
The