git: kernel - work around ipmi serial port bug

Matthew Dillon dillon at crater.dragonflybsd.org
Mon Oct 14 18:29:50 PDT 2013


commit 32a1602cb6629944188c894406dbfd736f1282c2
Author: Matthew Dillon <dillon at backplane.com>
Date:   Mon Oct 14 18:27:17 2013 -0700

    kernel - work around ipmi serial port bug
    
    * On our supermicro blade server the ipmi can get confused when the
      host initializes the 16550A and may fail to clear the RXRDY interrupt
      status, resulting in an endless loop.
    
      This appears to only occur when interrupts are enabled early to support
      kern.alt_break_to_debugger on a serial console.
    
    * Issuing a dummy read of the RXDATA register appears to unstick the ipmi.
      Go figure.

Summary of changes:
 sys/dev/serial/sio/sio.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/32a1602cb6629944188c894406dbfd736f1282c2


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