Messages in this thread | | | Date | Tue, 27 Sep 2011 18:38:49 +0200 | From | Takashi Iwai <> | Subject | Re: S4 resume broken since 2.6.39 (3.1, too) |
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At Mon, 26 Sep 2011 19:26:44 -0700, Yinghai Lu wrote: > > On 09/22/2011 11:11 AM, Takashi Iwai wrote: > > > 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? > > > not sure. > > seems resume has it's own page table during transition... > > > > Any hint for further debugging? > > > you may try to insert dead loop in arch/x86/power/hibernate_asm_64.S::restore_image or core_restore_code > > to see which part cause reset.
That's the answer I was afraid of :)
Takashi
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