Re: suspend to ram problem

[Pavel Machek <pavel@ucw.cz>]

Hi!

>>>> Hmm, maybe I know where problem could be. Try
>>>>
>>>>         movl     $(wakeup_stack - wakeup_code), %esp              # 
>>>> Private stack is needed for ASUS bo\
>>>>
>>>> instead of existing stack setup. That helped on one of my test-boxes
>>> Thanks, I will try that.
>>> Because clearing the flags imply pop/push in the stack it could be the 
>>> problem
>> That doesn't help : it still crash in pushl $0.
>>
> All stack stuff in wakeup_code crash for me.
> I tried to change the stack position, make sure upper bit of %esp are 
> clear, ... nothing work.
> What's are strange is that according to my x86 manual, in real mode the 
> failure can only happen if the stack wrap which is not the case here.
> Any x86 guru advice ?

Could you try the .c wakeup? I changed it a bit, perhaps that's enough.

> If I remove stack access (remove clearing flag stuff, not call to video 
> stuff) the resume works.

Actually, I see a possible problem:

_start:
        cli
        cld

        /* Set up segments */
        movw    %cs,%ax
        movw    %ax,%ds
        movw    %ax,%es
        movw    %ax,%ss

        movl    $wakeup_stack_end, %esp

        /* Clear the EFLAGS */
        pushl   $0
        popfl

...if someone calls start as 0x1234:0, we are okay. But if some broken
bios calls us as 0x1:0x234, we've got a problem.

One possible hack would be to movl 0, %esp. That should put the stack
at _start, corrupting memory but hopefully helping you diagnose it.
								Pavel
-- 
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