Re: Intel BIOS - Corrupted low memory at ffff880000004200

[Alexey Fisher]

Ingo Molnar schrieb:
> * Matthew Garrett <mjg59@xxxxxxxxxxxxx> wrote:
>
> > On Mon, Jul 06, 2009 at 06:24:47PM +0200, Alexey Fisher wrote:
> > > Hallo Ingo, Richard.
> > >
> > > I'm getting "Corrupted low memory" trace with my Intel DG45ID 
> > > board after resume. This board has different dmi-bios-vendor... 
> > > so probably it will be nice to have it in your patch.
> > I'm beginning to think that we should be doing this on all 
> > hardware, perhaps with a kernel option to disable it for embedded 
> > devices that really need that 64K. The low-memory corruption issue 
> > seems to be very widespread.
>
> The problem is that the BIOS corrupted memory that it also marked as 
> 'usable' in its E820 map it gave to the kernel. If that memory is 
> not usable, it should not have been marked as such. Also, some of 
> the reports showed corruption beyond this range so the workaround is 
> not universal.
>
> So i'd really like to know what is happening there, instead of just 
> zapping support for 64K of RAM on the majority of Linux systems.
>
> We might end up doing the same thing in the end (i.e. disable that 
> 64k of RAM) - but it should be an informed decision, not a wild stab 
> in the dark.
>
> 	Ingo

If i make memory dump like "dd if=/dev/mem of=memdump.dd bs=64k count=1" 
before and after suspend. Will it help you find out whats happening.
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