lost or missed Eth-Tx interrupts on high Traffic EMAC BF607

hi !

we observe troubles with missed or not occured ETH-TI ints on our board

using own written int-handler for rx/tx handling (derived from adi_gemac.c) which is working fine for low bandwith on the network,, we observe

troubles if we are cascaded on the network (3-5 hops) and a lot of multicast packets are within the network. (>40MBit/s)

our tx.routine is based on a queue which is linked in the int-routine after receiving a special clock packet which occurs each 1.3msec.

this list is a queue of ethernet frames and putted into the DMA queue. The last frame is configured to generate an interrupt to signal that tx queue is finished and DMA transfer completed

 emac_dmadesc_tx[desc_cnt-1].DES0_Status |= (ENUM_DS_TXENDOF_RING | ENUM_DS_TXINT_ENA); //int on the end of list -//sign last frame :: 

this int is not always generated or missed (BITM_EMAC_DMA_STAT_TI)  .. how can this happen?????