[Xen-devel] Re: [PATCH] watchdog, SP5100: Check if firmware has set correct value in tcobase.

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Thu, 17 Mar 2011, Konrad Rzeszutek Wilk wrote:
> On Wed, Mar 16, 2011 at 02:18:17PM -0700, Yinghai Lu wrote:
> > 
> > 
> > Stefano found SP5100 TCO watchdog driver using wrong address.
> > 
> > [    9.148536] SP5100 TCO timer: SP5100 TCO WatchDog Timer Driver v0.01
> > [    9.148628] DEBUG __ioremap_caller WARNING address=b8fe00 size=8 valid=1 
> > reserved=1
> > 
> > and e820 said that range is RAM.
> > 
> > We should check if we can use that reading out. BIOS could just program 
> > wrong address there.
> > 
> > -v2: Mike pointed out one path need one release.
> > 
> > Reported-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> > Signed-off-by:Yinghai Lu <yinghai@xxxxxxxxxx>
> > Acked-by: Mike Waychison <mikew@xxxxxxxxxx>
> 
> I have no idea why it worked the first time b/c this:
> 
> 
> > +   if (request_mem_region_exclusive(val, SP5100_WDT_MEM_MAP_SIZE, "SP5100 
> > TCO")) {
> 
> is wrong. It should have been "if (!request...")..
> 
> With that, and with Stefano's patches (stefano/2.6.38-rc6-mm-fix) on top of 
> 2.6.39-rc0 it boots up fine.

Yinghai, thanks for the patch!
I hope that we are not going to find any more of this kind of issues
with other drivers and other BIOSes.

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