Minimum Signal Current for DALI Driver
The maximum, not nominal, current draw for a driver (which are usually mains powered, this doesn't apply to bus powered) is 2mA, this is over the voltage range 0 to 22.5V and the temperature range. It applies when the driver is not transmitting, because when transmitting the driver pulls the line down to the current limit of the supply, maximum 250mA.
The minimum current consumption when not transmitting is 10uA over the voltage range of (threshold voltage of the receiver) to 22.5V.

Additionally, there are requirements on power supplies in IEC62386-101 which you should have if you are working with DALI. 12V does meet the output voltage minimum of 12.0V over full input voltage range, load range, temperature but the supply must produce a guaranteed minimum supply current of 8.0mA at 12.0V over the temperature range.

Whilst most LED drivers and other such control gear are mains powered, it is allowable to have bus powered gear, and many control devices such as sensors are bus powered. These do not have an additional mains or other power input and draw their power from the DALI bus. In that case they are allowed to draw nearly 250mA but must specify what they draw when not transmitting so that a system designer can specify the power supply correctly.