cvs commit: src/sys/dev/bge if_bge.c

[Bjoern A. Zeeb]

bz          2008-04-08 11:51:17 UTC

  FreeBSD src repository

  Modified files:
    sys/dev/bge          if_bge.c 
  Log:
  In some situations we were not clearing pending link state attentions.
  Because of this we were not getting further interrupts for link state
  changes, thus never went into iface UP state and thus could not transmit.
  
  The only way out of this was an incoming packet generating an rx interrupt
  and making us call into bge_link_upd.
  
  Up to rev. 1.101, in bge_start_locked, we only returned instantly
  if there was 'no link AND nothing queued for tx'. So with a packet queued
  for tx, we hit the register scrubbing at the end of bge_start_locked
  and were out fine. We simply lost a packet or two but got the interrupts
  need to get into UP state.
  With rev. 1.102 this was turned into 'if there is no link OR there is
  nothing to send' (correct behaviour) and as long as there is no link
  we never hit the register scrubbing and consequently never got the link UP.
  
  What we do now is force an interrupt at the end of bge_ifmedia_upd_locked
  so we will call bge_link_upd, clear the link state attention and get
  further interrupts.
  This helps to get the iface UP on an idle network or at least to get
  it UP faster not depending on an rx intr anymore.
  In case you could not get a DHCP lease or it took very long,
  it was because of this.
  
  It is unknown which chips are affected by this. ASIC rev. 0x2003 was the
  most popular trouble candidate.
  At least the fiber cards should have been working fine.
  
  Which register to scrub is currently under discussion. The comitted
  solution was tested and found to work for a lot of setups. It might
  not help with MSI.
  The reason why we end up in such a situation is entirely unknown.
  
  PR:             kern/111804
  Tested by:      phk, scottl at Y!
  MFC after:      14 days
  
  Revision  Changes    Path
  1.205     +17 -0     src/sys/dev/bge/if_bge.c