DragonFly On-Line Manual Pages
RADEONKMS(4) DragonFly Kernel Interfaces Manual RADEONKMS(4)
NAME
radeonkms -- Driver for AMD/ATI Radeon graphics chipsets
DESCRIPTION
The radeonkms driver provides support for the AMD Radeon graphics chips.
Please refer the Loader Tunables section in syscons(4) for more informa-
tion about how to make the console work with radeonkms.
LOADER TUNABLES
Tunables can be set at the loader(8) prompt before booting the kernel or
stored in loader.conf(5).
drm.radeon.no_wb
Disables AGP writeback for scratch registers.
drm.radeon.dynclks
Enable/Disable dynamic clocks
drm.radeon.msi
Enable/Disable MSI (message signaled interrupts) 1 = enable, 0 =
disable, -1 = auto (default)
drm.radeon.fastfb
Direct FB access for IGP chips, which can significantly improve
performance for some applications. This option only affects the
RS690, RS780 and RS880 chipsets, and only when no sideport memory
is available. 1 = enable, 0 = disable (default)
drm.radeon.dpm
DPM (dynamic power management) support. 1 = enable, 0 = disable,
-1 = auto (default)
drm.radeon.backlight
Backlight support. 1 = enable, 0 = disable, -1 = auto (default)
SYSCTL VARIABLES
If display backlight level can be controlled by the GPU (which is often
the case in notebooks), the sysctl hw.backlight_level can be used to
adjust the backlight level. Permitted values are from 0 to the value
returned from the hw.backlight_max sysctl. On older Radeon GPU models
than the R600 series, the hw.backlight_level and hw.backlight_max sysctl
variables are no longer available by default. Setting the
drm.radeon.backlight tunable to ``1'' will force-enable native backlight
control via the sysctl variables in this case.
SEE ALSO
drm(4), syscons(4)
HISTORY
The radeonkms driver was first available for Linux.
BUGS
Enabling drm.radeon.fastfb on RS690 chipsets can cause graphics corrup-
tion when hardware acceleration is used. Display backlight control with
the hw.backlight_level sysctl is only supported for chipsets using Atom-
BIOS (which includes some R400 chipsets and all later generations).
DragonFly 5.5 November 20, 2015 DragonFly 5.5