seth bollinger

FEC driver problem on i.mx25

Discussion created by seth bollinger on Oct 12, 2011
Latest reply on May 22, 2012 by wolfgang gaerber

Hello All,


Sometimes the FEC driver will stall with a descriptor in the DMA ring that's ready for transmit but FEC_X_DES_ACTIVE bit is not enabled.  This buffer will remain jammed in the ring until another transmit request is queued.


Has anyone else seen this issue?  Is there a known solution?


We have worked around the problem by keeping a count of tx ready descriptor, then we check that count at the end of fec_enet_rx().  If we have at least one tx descriptor ready, but the DMA TX controller is not active, we give it a bump.


We would like to avoid this situation rather than work around it.