[PATCH] ACPI: Correctly recover from a failed S3 attempt
From: William Morrrow <[email protected]>
This was discovered on a broken BIOS that simply returned from its
suspend procedure, appearing to the OS as a failed S3 attempt.
It is possible to invoke the protected mode register restore routine (which
would normally restore the sysenter registers) when the bios returns from S3.
This has no effect on a correctly running system and repairs the damage
from broken BIOS.
Signed-off-by: William Morrow <[email protected]>
Signed-off-by: Jordan Crouse <[email protected]>
---
arch/i386/kernel/acpi/wakeup.S | 5 ++++-
1 files changed, 4 insertions(+), 1 deletions(-)
diff --git a/arch/i386/kernel/acpi/wakeup.S b/arch/i386/kernel/acpi/wakeup.S
index 9f408ee..b781b38 100644
--- a/arch/i386/kernel/acpi/wakeup.S
+++ b/arch/i386/kernel/acpi/wakeup.S
@@ -292,7 +292,10 @@ ENTRY(do_suspend_lowlevel)
pushl $3
call acpi_enter_sleep_state
addl $4, %esp
- ret
+
+# In case of S3 failure, we'll emerge here. Jump
+# to ret_point to recover
+ jmp ret_point
.p2align 4,,7
ret_point:
call restore_registers
Hi!
> We have a poorly behaving BIOS that simply returns from its suspend
> procedure, rather then jumping to the restart routine indicated by
> the FACS. This appears to Linux as a failed S3 attempt.
>
> This would normally succeed, but the sysenter msrs are not
> restored and the restart fails. It is not clear if this is the only
> omission, but if the sysenter msrs are manually entered in the debugger,
> the OS resumes.
>
> The attached patch would invoke the register restore function on failure.
> This has absolutely no effect on correct systems, and, "does the right thing"
> for failed or stupid BIOSes, at least as far as I am concerned.
Can we get fixed bios, too?
What machines are affected?
> --- a/arch/i386/kernel/acpi/wakeup.S
> +++ b/arch/i386/kernel/acpi/wakeup.S
> @@ -292,7 +292,10 @@ ENTRY(do_suspend_lowlevel)
> pushl $3
> call acpi_enter_sleep_state
> addl $4, %esp
> - ret
> +
> +# In case of S3 failure, we'll emerge here. Jump
> +# to ret_point to recover
> + jmp ret_point
> .p2align 4,,7
%esp manipulation is now unneccessary?
Can we somehow propagate the error condition?
Why jmp when ret_point is next instruction?
> ret_point:
> call restore_registers
--
Thanks for all the (sleeping) penguins.