All MDI transmit data is handled in the uwput(D2mdi) upper-write put entry point routine and by the intr(D2mdi) interrupt routine.
An MDI driver should not include any STREAMS queue service procedures; for more information, see intr(D2mdi) and uwput(D2mdi). Nonetheless, it should make use of the STREAMS write queue. Reasonable low and high water-marks for the STREAMS write queue of an MDI driver are:
This allows approximately 25 frames to be queued for
transmission before frames are flow-controlled.
module assumes that the hardware is inactive
if the MDI driver does not remove
from the write queue every NET0_TXMONCNSMT clock ticks.