Re: [PATCH] ACPI: x86: Adjust Microsoft LPS0 _DSM handling sequence

["Limonciello, Mario" <mario.limonciello@xxxxxxx>]

On 6/1/2023 10:06 PM, David E. Box wrote:
> On Thu, 2023-06-01 at 20:46 -0500, Limonciello, Mario wrote:
> > On 6/1/2023 8:31 PM, David E. Box wrote:
> > > On Thu, 2023-06-01 at 18:39 -0500, Mario Limonciello wrote:
> > > > In Windows the Microsoft _DSM doesn't call functions 3->5->7 for suspend
> > > > and 8->6->4 for resume like Linux currently does.
> > > >
> > > > Rather it calls 3->7->5 for suspend and 6->8->4 for resume.
> > > > Align this calling order for Linux as well.
> > > >
> > > > Link:
> > > > https://learn.microsoft.com/en-us/windows-hardware/design/device-experiences/modern-standby-states
> > > I didn't catch the ordering in the link.
> > Yeah it's tough to interpret from the link, because the picture at the
> > bottom
> > is missing annotations.
> >
> > Basically if you look at the picture the blue part is the screen on/off.
> >
> > The green part is "modern standby" and then the little "humps" are LPS0
> > enter/exit.
> >
> > > Was there any issue that prompted this
> > > change?
> >
> > We were debugging an unrelated problem and noticed the difference
> > comparing the
> >
> > BIOS debugging log from Windows and Linux.
> >
> > If an OEM depends on this call order in that code used in LPS0 phase
> > requires
> > changes from MS phase I could hypothesize this fixes it.
> >
> >
> > > David
> > BTW - is there interest in supporting the Microsoft _DSM GUID for Intel
> > side too?
> >
> > It's an incongruity today that we run both AMD GUID and Microsoft GUID
> > for AMD systems
> > but only run Intel GUID for Intel systems.
> There hasn't been a need yet. Rafael have you look at it?
>
> David

AFAICT from Linux side it should be a one line patch to drop:

        lps0_dsm_func_mask_microsoft = -EINVAL;

> > > > Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
> > > > ---
> > > >    drivers/acpi/x86/s2idle.c | 14 +++++++-------
> > > >    1 file changed, 7 insertions(+), 7 deletions(-)
> > > >
> > > > diff --git a/drivers/acpi/x86/s2idle.c b/drivers/acpi/x86/s2idle.c
> > > > index e499c60c4579..7214197c15a0 100644
> > > > --- a/drivers/acpi/x86/s2idle.c
> > > > +++ b/drivers/acpi/x86/s2idle.c
> > > > @@ -485,11 +485,11 @@ int acpi_s2idle_prepare_late(void)
> > > >                                           ACPI_LPS0_ENTRY,
> > > >                                           lps0_dsm_func_mask,
> > > > lps0_dsm_guid);
> > > >           if (lps0_dsm_func_mask_microsoft > 0) {
> > > > -               acpi_sleep_run_lps0_dsm(ACPI_LPS0_ENTRY,
> > > > -                               lps0_dsm_func_mask_microsoft,
> > > > lps0_dsm_guid_microsoft);
> > > >                   /* modern standby entry */
> > > >                   acpi_sleep_run_lps0_dsm(ACPI_LPS0_MS_ENTRY,
> > > >                                   lps0_dsm_func_mask_microsoft,
> > > > lps0_dsm_guid_microsoft);
> > > > +               acpi_sleep_run_lps0_dsm(ACPI_LPS0_ENTRY,
> > > > +                               lps0_dsm_func_mask_microsoft,
> > > > lps0_dsm_guid_microsoft);
> > > >           }
> > > >    
> > > >           list_for_each_entry(handler, &lps0_s2idle_devops_head, list_node)
> > > > {
> > > > @@ -524,11 +524,6 @@ void acpi_s2idle_restore_early(void)
> > > >                   if (handler->restore)
> > > >                           handler->restore();
> > > >    
> > > > -       /* Modern standby exit */
> > > > -       if (lps0_dsm_func_mask_microsoft > 0)
> > > > -               acpi_sleep_run_lps0_dsm(ACPI_LPS0_MS_EXIT,
> > > > -                               lps0_dsm_func_mask_microsoft,
> > > > lps0_dsm_guid_microsoft);
> > > > -
> > > >           /* LPS0 exit */
> > > >           if (lps0_dsm_func_mask > 0)
> > > >                   acpi_sleep_run_lps0_dsm(acpi_s2idle_vendor_amd() ?
> > > > @@ -539,6 +534,11 @@ void acpi_s2idle_restore_early(void)
> > > >                   acpi_sleep_run_lps0_dsm(ACPI_LPS0_EXIT,
> > > >                                   lps0_dsm_func_mask_microsoft,
> > > > lps0_dsm_guid_microsoft);
> > > >    
> > > > +       /* Modern standby exit */
> > > > +       if (lps0_dsm_func_mask_microsoft > 0)
> > > > +               acpi_sleep_run_lps0_dsm(ACPI_LPS0_MS_EXIT,
> > > > +                               lps0_dsm_func_mask_microsoft,
> > > > lps0_dsm_guid_microsoft);
> > > > +
> > > >           /* Screen on */
> > > >           if (lps0_dsm_func_mask_microsoft > 0)
> > > >                   acpi_sleep_run_lps0_dsm(ACPI_LPS0_SCREEN_ON,