hvc_console change results in corrupt oops output

Benjamin Herrenschmidt benh at kernel.crashing.org
Tue Jul 5 16:22:43 EST 2011

On Tue, 2011-07-05 at 04:17 +0000, Tabi Timur-B04825 wrote:
> On Mon, Jul 4, 2011 at 9:24 AM, Hendrik Brueckner
> <brueckner at linux.vnet.ibm.com> wrote:
> > I will check this again for my hvc_iucv back-end.  Meanwhile a found
> > an old thread discussing the same issue.  It covers some differences
> > between console and ttys which actually does not matter for hvc-backend
> > because of the shared put_chars() routine.
> >
> > You can read the thread on lkml.org: http://lkml.org/lkml/2009/10/15/149
> I started that thread.  After much soul searching, we came to the
> conclusion that HVC is not compatible with hypervisors that return
> BUSY on writes. 

That is a fun conclusion considering that hvc has been written for the
pseries hypervisor which ... can return BUSY on writes :-)

> So I threw out my HVC driver and rewrote it as a
> standard console and TTY driver.  That driver is waiting to be
> included in the 3.1 kernel.


We just need to fix HVC properly.


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