Re: S4 resume broken since 2.6.39 (3.1, too)

[Takashi Iwai <tiwai@suse.de>]

At Thu, 22 Sep 2011 07:33:17 -0700,
Yinghai Lu wrote:
> 
> On Wed, Sep 21, 2011 at 11:48 AM, Rafael J. Wysocki <rjw@sisk.pl> wrote:
> > It looks like init_memory_mapping() is sometimes called with "end"
> > beyond the last mapped PFN and it explodes when we try to write stuff to
> > that address during image restoration.
> >
> > IOW, the Yinghai's assumption that init_memory_mapping() would always be
> > called with a "good end" on x86_64 was overomptimistic.
> 
> for 64bit x86, kernel_physical_mapping_init() will use
> map_low_page()/call early_memmap() to access ram for page_table that is above
> rather last mapped PFN.
> 
> the point is:
> on system with 64g, usable ram will be [0,2048m), [4g, 64g)
> init_memory_mapping will be called two times for them.
> before putting page_table high,
> page table will be two parts: one is just below 512M, and one below 2048m.
> after putting page_table high,
> page table will be two parts: one is just below 2048M, and one below 64G.

So, how can this change break S4 resume?
Any hint for further debugging?


thanks,

Takashi