bge(4) one packet wedge

Pyun YongHyeon pyunyh at gmail.com
Thu Aug 24 01:47:49 UTC 2006


On Wed, Aug 23, 2006 at 12:53:49PM -0700, David Christensen wrote:
 > This "lost interrupt" type of problem is addressed by the use of the
 > status_tag 
 > field in the status block.  (Listed as bge_rsvd0 in the bge_status_block
 > structure). 
 > Everytime the status block is updated a new tag value is written to the
 > status block.  
 > When the ISR starts the driver should record the status_tag value.  At
 > the end
 > of the ISR, the driver should compare the current status_tag value is
 > the status
 > block with the value recorded on entry to the ISR.  If the values are
 > the same
 > then no additional status block updates have occurred so there shouldn't
 > be
 > any packets hanging around.  If the values are different then additional
 > packets
 > or completions are waiting around so the ISR should loop around again.
 > At the 
 > end of the ISR the driver will write the status_tag value it last
 > handled to a
 > mailbox register, letting the hardware know the last status block update
 > handled.
 > If necessary the hardware will generate a new interrupt and start the
 > process over
 > again.
 > 
 > This entire process should be included in the Linux driver, I don't see
 > it being
 > used in the bge driver (bge_intr()).
 > 

Hi,

I have a question too.
How we know generated interrupt is ours?
It seems that status block could be updated before/after generation
of an interrupt. If the interrupt is shared with other devices
what is correct way to know the origion of the interrupt?

-- 
Regards,
Pyun YongHyeon


More information about the freebsd-net mailing list