The tac message can only occur when a packet is queued by the queue layer
with dev->tbusy=0 and by the time it hits the device driver dev->tbusy=1.
That implies the following occurs
That doesn't leave a lot of suspect code around - probably the code that
handles the 3c590 TX FIFO bug. There is definitely some suspect code in
there because nothing protects an interrupt from interrupting the
Possibly there should be a save_flags();cli()....;restore_flags() around
the code bracketed by the if(dev->tbusy) in vortex_start_xmit() ?