Re: [PATCH] sky2: receive dma mapping error handling

[Michael Breuer]

On 01/30/2010 07:34 PM, Jarek Poplawski wrote:
> On Sat, Jan 30, 2010 at 11:31:48AM -0500, Michael Breuer wrote:
>    
> > On 01/28/2010 06:36 PM, Stephen Hemminger wrote:
> >      
> > > Please try this patch (and only this patch), on 2.6.33-rc5[*];
> > > none of the other patches that did not make it upstream because that
> > > confuses things too much.
> > >
> > > The code that checks for DMA mapping errors on receive buffers would
> > > not handle errors correctly.  I doubt you have these errors, but if you
> > > did then it would explain the problems.  The code has to be a little
> > > tricky and build mapping for new rx buffer before releasing old one,
> > > that way if new mapping fails, the old one can be reused.
> > >
> > > If it works for you, I will resubmit with signed-off.
> > >
> > > -
> > >
> > >        
> > Nope - tx crash again. This time the system stayed up (but hosed)
> > for a few hours. When I tried to recover eth0 the system then
> > crashed.
> >
> > Brief summary of events (log extract below):
> >
> > System start Jan 28 19:29
> > Everything seemed good (load and all) until 17:13:11 the following
> > day when I got rx errors:
> >
> > Jan 29 17:13:11 mail kernel: sky2 eth0: rx error, status 0x6230010
> > length 1518
> > Jan 29 17:13:11 mail kernel: sky2 eth0: rx error, status 0x7f40010
> > length 1518
> >      
> These are length errors, but status shows more than 1518, e.g. 2036
> here, unless I miss something. Please, don't use jumbo frames in your
> network until we fully debug it for regular frames (Stephen admitted
> sky2 jumbo might be broken).
>    
MTU was 1500 - not using jumbo frames as they don't work.
> ...
>    
> > As I started looking at logs, the system hung and rebooted. I'm up
> > now with dma debug enabled, however as with 2.6.32.4 num_entries is
> > dropping and I don't think that dma debug will remain enabled long
> > enough to catch a crash.
> >      
> Could you try the patch below to show maybe some other users of
> dma-debug entries?
>
> Jarek P.
> ---
>    
Will do. Note that I'm running with the dma debug filter set to sky2.
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