[root@arch arch]# ls -l /sys/bus/i2c/devices/
итого 0
lrwxrwxrwx 1 root root 0 ноя 10 10:15 i2c-0 -> ../../../devices/pci0000:00/0000:00:02.0/0000:01:00.0/i2c-0
lrwxrwxrwx 1 root root 0 ноя 10 10:15 i2c-1 -> ../../../devices/pci0000:00/0000:00:02.0/0000:01:00.0/i2c-1
lrwxrwxrwx 1 root root 0 ноя 10 10:15 i2c-2 -> ../../../devices/pci0000:00/0000:00:02.0/0000:01:00.0/i2c-2
lrwxrwxrwx 1 root root 0 ноя 10 10:15 i2c-3 -> ../../../devices/pci0000:00/0000:00:02.0/0000:01:00.0/i2c-3
lrwxrwxrwx 1 root root 0 ноя 10 10:15 i2c-4 -> ../../../devices/pci0000:00/0000:00:02.0/0000:01:00.0/i2c-4
lrwxrwxrwx 1 root root 0 ноя 10 10:15 i2c-5 -> ../../../devices/pci0000:00/0000:00:02.0/0000:01:00.0/i2c-5
lrwxrwxrwx 1 root root 0 ноя 10 10:15 i2c-6 -> ../../../devices/pci0000:00/0000:00:02.0/0000:01:00.0/i2c-6

cat /sys/module/radeon/parameters/hw_i2c
0

modinfo -p radeon
no_wb:Disable AGP writeback for scratch registers (int)
modeset:Disable/Enable modesetting (int)
dynclks:Disable/Enable dynamic clocks (int)
r4xx_atom:Enable ATOMBIOS modesetting for R4xx (int)
vramlimit:Restrict VRAM for testing, in megabytes (int)
agpmode:AGP Mode (-1 == PCI) (int)
gartsize:Size of PCIE/IGP gart to setup in megabytes (32, 64, etc., -1 = auto) (int)
benchmark:Run benchmark (int)
test:Run tests (int)
connector_table:Force connector table (int)
tv:TV enable (0 = disable) (int)
audio:Audio enable (-1 = auto, 0 = disable, 1 = enable) (int)
disp_priority:Display Priority (0 = auto, 1 = normal, 2 = high) (int)
hw_i2c:hw i2c engine enable (0 = disable) (int)
pcie_gen2:PCIE Gen2 mode (-1 = auto, 0 = disable, 1 = enable) (int)
msi:MSI support (1 = enable, 0 = disable, -1 = auto) (int)
lockup_timeout:GPU lockup timeout in ms (default 10000 = 10 seconds, 0 = disable) (int)
fastfb:Direct FB access for IGP chips (0 = disable, 1 = enable) (int)
dpm:DPM support (1 = enable, 0 = disable, -1 = auto) (int)
aspm:ASPM support (1 = enable, 0 = disable, -1 = auto) (int)
runpm:PX runtime pm (1 = force enable, 0 = disable, -1 = PX only default) (int)
hard_reset:PCI config reset (1 = force enable, 0 = disable (default)) (int)
vm_size:VM address space size in gigabytes (default 4GB) (int)
vm_block_size:VM page table size in bits (default depending on vm_size) (int)
deep_color:Deep Color support (1 = enable, 0 = disable (default)) (int)
use_pflipirq:Pflip irqs for pageflip completion (0 = disable, 1 = as fallback, 2 = exclusive (default)) (int)
bapm:BAPM support (1 = enable, 0 = disable, -1 = auto) (int)
backlight:backlight support (1 = enable, 0 = disable, -1 = auto) (int)
auxch:Use native auxch experimental support (1 = enable, 0 = disable, -1 = auto) (int)
mst:DisplayPort MST experimental support (1 = enable, 0 = disable) (int)

 modinfo -p radeon | grep i2c
hw_i2c:hw i2c engine enable (0 = disable) (int)

acpitz-virtual-0
Adapter: Virtual device
temp1:        +43.0°C  

k10temp-pci-00c3
Adapter: PCI adapter
temp1:        +44.0°C  (high = +70.0°C)
                       (crit = +115.5°C, hyst = +110.5°C)

radeon-pci-0008
Adapter: PCI adapter
temp1:         +2.0°C  (crit = +120.0°C, hyst = +90.0°C)

fam15h_power-pci-00c4
Adapter: PCI adapter
power1:           N/A  (crit =  95.09 W)

k10temp-pci-00c3
Adapter: PCI adapter
temp1:         +2.1°C  (high = +70.0°C)
                       (crit = +80.0°C, hyst = +79.0°C)

lsmod |grep i2c
i2c_algo_bit            5136  2 radeon,nouveau
i2c_piix4               8537  0

lsmod |grep i2c
i2c_algo_bit           16384  1 radeon
modprobe i2c_piix4
lsmod |grep i2c
i2c_algo_bit           16384  1 radeon

 ~  » lsmod |grep i2c
i2c_piix4              20480  0
i2c_algo_bit           16384  1 radeon

i2c_algo_bit  hw_i2c=1

[br]i2c_piix4  hw_i2c=1[br]

radeon hw_i2c=1

modinfo -p radeon | grep i2