Re: Bug#234976: kernel-source-2.6.4: Software Suspend doesn't work

From: Pavel Machek (pavel_at_suse.cz)
Date: 04/27/04

  • Next message: Alexander Gran: "e1000 EEPROM wrong after suspending." 
    Date:	Tue, 27 Apr 2004 23:52:36 +0200
To: Herbert Xu <herbert@gondor.apana.org.au>, Andrew Morton <akpm@zip.com.au>

    Hi!

    > > --- tmp/linux/arch/i386/power/cpu.c 2003-09-28 22:05:30.000000000 +0200
    > > +++ linux/arch/i386/power/cpu.c 2004-04-27 14:44:03.000000000 +0200
    > > @@ -35,6 +35,9 @@
    > > unsigned long saved_context_esi, saved_context_edi;
    > > unsigned long saved_context_eflags;
    > >
    > > +/* Special page directory for resume */
    > > +char swsusp_pg_dir[PAGE_SIZE];
    > > +
    >
    > You forgot to mark this as nosave.

    More importantly, I forgot to mark it as aligned on PAGE_SIZE. Oops
    (er... double fault). Here's fixed patch, and this one should work.

    Andrew, the crashes with intel-agp were not driver fault after
    all. swsusp assumed 4MB pages, and intel-agp driver broke 4MB page
    down, resulting in nasty crash.

    Herbert's solution was to copy memory backwards, and avoid the crash
    by luck (But thanks a lot for explaining me the problem!).

    Non-PSE cpus are still not supported; but it should be easier when we
    are running in pagedir with identity-mapped pages.

    This solution copies page table at boot, where it is "known good",
    still 4MB. Could you apply it?

                                                                    Pavel

    --- tmp/linux/arch/i386/mm/init.c 2004-04-05 10:45:11.000000000 +0200
    +++ linux/arch/i386/mm/init.c 2004-04-27 23:39:07.000000000 +0200
    @@ -331,6 +331,13 @@
     void zap_low_mappings (void)
     {
             int i;
    +
    +#ifdef CONFIG_SOFTWARE_SUSPEND
    + {
    + extern char swsusp_pg_dir[PAGE_SIZE];
    + memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE);
    + }
    +#endif
             /*
              * Zap initial low-memory mappings.
              *
    --- tmp/linux/arch/i386/power/cpu.c 2003-09-28 22:05:30.000000000 +0200
    +++ linux/arch/i386/power/cpu.c 2004-04-27 23:41:01.000000000 +0200
    @@ -35,6 +35,10 @@
     unsigned long saved_context_esi, saved_context_edi;
     unsigned long saved_context_eflags;
     
    +/* Special page directory for resume */
    +char __nosavedata swsusp_pg_dir[PAGE_SIZE]
    + __attribute__ ((aligned (PAGE_SIZE)));
    +
     extern void enable_sep_cpu(void *);
     
     void save_processor_state(void)
    --- tmp/linux/arch/i386/power/swsusp.S 2003-09-28 22:05:30.000000000 +0200
    +++ linux/arch/i386/power/swsusp.S 2004-04-27 14:41:54.000000000 +0200
    @@ -29,7 +38,7 @@
             jmp .L1449
             .p2align 4,,7
     .L1450:
    - movl $swapper_pg_dir-__PAGE_OFFSET,%ecx
    + movl $swsusp_pg_dir-__PAGE_OFFSET,%ecx
             movl %ecx,%cr3
     
             call do_magic_resume_1
    --- tmp/linux/include/asm-i386/suspend.h 2003-09-28 22:06:36.000000000 +0200
    +++ linux/include/asm-i386/suspend.h 2004-04-27 23:10:24.000000000 +0200
    @@ -9,6 +9,9 @@
     static inline int
     arch_prepare_suspend(void)
     {
    + /* If you want to make non-PSE machine work, turn off paging
    + in do_magic. swsusp_pg_dir should have identity mapping, so
    + it could work... */
             if (!cpu_has_pse)
                     return -EPERM;
             return 0; 

    -- 
934a471f20d6580d5aad759bf0d97ddc
-
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