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.Dd October 9, 2019
.Dt RADEON 4
.Os
.Sh NAME
.Nm radeon
.Nd Driver for AMD/ATI Radeon graphics chipsets
.Sh DESCRIPTION
The
.Nm
driver provides support for the AMD Radeon graphics chips.
Please refer the
.Sx Loader Tunables
section in
.Xr syscons 4
for more information about how to make the console work with
.Nm .
.Sh LOADER TUNABLES
Tunables can be set at the
.Xr loader 8
prompt before booting the kernel or stored in
.Xr loader.conf 5 .
.Bl -tag -width "xxxxxx"
.It Va drm.radeon.no_wb
Disables AGP writeback for scratch registers.
.It Va drm.radeon.dynclks
Enable/Disable dynamic clocks
.\".It Va drm.radeon.r4xx_atom
.\"XXX
.\".It Va drm.radeon.vram_limit
.\"XXX
.\".It Va drm.radeon.agpmode
.\"XXX
.\".It Va drm.radeon.gart_size
.\"XXX
.\".It Va drm.radeon.benchmarking
.\"XXX
.\".It Va drm.radeon.testing
.\"XXX
.\".It Va drm.radeon.connector_table
.\"XXX
.\".It Va drm.radeon.tv
.\"XXX
.\".It Va drm.radeon.audio
.\"XXX
.\".It Va drm.radeon.disp_priority
.\"XXX
.\".It Va drm.radeon.hw_i2c
.\"XXX
.\".It Va drm.radeon.pcie_gen2
.\"XXX
.It Va drm.radeon.msi
Enable/Disable MSI (message signaled interrupts)
1 = enable, 0 = disable, -1 = auto (default)
.\".It Va drm.radeon.lockup_timeout
.\"XXX
.It Va 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)
.It Va drm.radeon.dpm
DPM (dynamic power management) support.
1 = enable, 0 = disable, -1 = auto (default)
.\".It Va drm.radeon.aspm
.\"XXX
.It Va drm.radeon.backlight
Backlight support.
1 = enable, 0 = disable, -1 = auto (default)
.El
.Sh SYSCTL VARIABLES
If display backlight level can be controlled by the GPU (which is often
the case in notebooks), the sysctl
.Va hw.backlight_level
can be used to adjust the backlight level.
Permitted values are from 0 to the value returned from the
.Va hw.backlight_max
sysctl.
On older Radeon GPU models than the R600 series, the
.Va hw.backlight_level
and
.Va hw.backlight_max
sysctl variables are no longer available by default.
Setting the
.Va drm.radeon.backlight
tunable to
.Dq 1
will force-enable native backlight control via the
sysctl variables in this case.
.Sh SEE ALSO
.Xr drm 4 ,
.Xr syscons 4
.Sh HISTORY
The
.Nm
driver was first available for Linux.
.Sh BUGS
Enabling
.Va drm.radeon.fastfb
on RS690 chipsets can cause graphics corruption when hardware acceleration
is used.
Display backlight control with the
.Va hw.backlight_level
sysctl is only supported for chipsets using AtomBIOS (which includes some
R400 chipsets and all later generations).