Name
z8530_tx_begin — 
     Begin packet transmission
 
Synopsis
| void z8530_tx_begin ( | struct z8530_channel * c ); | 
 
Arguments
- c
- 
     The Z8530 channel to kick
     
Description
   This is the speed sensitive side of transmission. If we are called
   and no buffer is being transmitted we commence the next buffer. If
   nothing is queued we idle the sync. 
Note
   We are handling this code path in the interrupt path, keep it
   fast or bad things will happen.
   
   Called with the lock held.