Specifications

Appendix C. Supported graphics
cards
/dev/i2c-* versus PCI memory
To control a monitor, DDCcontrol must access to the I2C bus of the graphics card. There are two
methods to do so: the first one uses /dev/i2c-* devices provided by kernel drivers (abbreviated
by dev in tables), the second one reads and writes directly in the card PCI memory (abbreviated by
PCI in the tables).
Depending on your hardware, one method or the other works, or even both.
ATI Radeon series
Direct PCI memory access support
Almost every ATI cards should work with direct PCI memory access, even if it has not been very
extensively tested.
To use it, you have nothing special to do, everything is done by DDCcontrol.
/dev/i2c-* devices support
ATI Radeon cards also work with /dev/i2c-* devices. To use /dev/i2c-* devices with ATI
cards, you must load the radeonfb module by typing, as root:
# modprobe radeonfb
The kernel configuration options needed to enable Radeon framebuffer driver and I2C support are:
• Devices drivers->Graphics support->Framebuffer support->ATI Radeon display support.
• Devices drivers->Graphics support->Framebuffer support->ATI Radeon display support-
>DDC/I2C for ATI Radeon support.
Warning
The radeonfb kernel module may cause system instability (crashes or screen corruption)
when used at the same time as used the ATI closed source drivers.
This is why we recommend that you use direct PCI memory access with ATI cards.
ATI cards support table
These ATI cards have been reported to work, but others models should also work. If yours is not lis-
ted, please send a message to one of the DDCcontrol mailing lists (see Appendix A, Report prob-
lems and successes).
Name
Works
dev PCI
Radeon 7000 Yes ???
Radeon 7500 Yes ???
10