As far as I know the "no S3 if SMT off" is just an oddity of the particular BIOS I got on the "B550I AORUS PRO AX". Also, what has changed that would prevent the same issue I was hitting before?: https://gitlab.freedesktop.org/drm/amd/-/issues/2364#note_1735422 Cheers, Rafael "Limonciello, Mario" <Mario.Limonciello@xxxxxxx> writes: > [AMD Official Use Only - General] > >> -----Original Message----- >> From: Alex Deucher <alexdeucher@xxxxxxxxx> >> Sent: Tuesday, May 30, 2023 1:16 PM >> To: Limonciello, Mario <Mario.Limonciello@xxxxxxx> >> Cc: amd-gfx@xxxxxxxxxxxxxxxxxxxxx; Rafael Ávila de Espíndola >> <rafael@xxxxxxxxxx> >> Subject: Re: [PATCH 1/2] drm/amd: Disallow s0ix without BIOS support again >> >> On Tue, May 30, 2023 at 1:53 PM Mario Limonciello >> <mario.limonciello@xxxxxxx> wrote: >> > >> > commit cf488dcd0ab7 ("drm/amd: Allow s0ix without BIOS support") >> showed >> > improvements to power consumption over suspend when s0ix wasn't >> enabled in >> > BIOS and the system didn't support S3. >> > >> > This patch however was misguided because the reason the system didn't >> > support S3 was because SMT was disabled in OEM BIOS setup. >> > This prevented the BIOS from allowing S3. >> > >> > Also allowing GPUs to use the s2idle path actually causes problems if >> > they're invoked on systems that may not support s2idle in the platform >> > firmware. `systemd` has a tendency to try to use `s2idle` if `deep` fails >> > for any reason, which could lead to unexpected flows. >> > >> > To make this the behavior discoverable and expected, revert commit >> > cf488dcd0ab7 ("drm/amd: Allow s0ix without BIOS support") and offer >> > a message if SMT appears to be disabled. >> > >> > Cc: Rafael Ávila de Espíndola <rafael@xxxxxxxxxx> >> > Link: >> https://github.com/torvalds/linux/blob/v6.1/drivers/gpu/drm/amd/amdgpu >> /amdgpu_acpi.c#L1060 >> > Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/2599 >> > Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx> >> > --- >> > drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c | 16 ++++++++++++++-- >> > 1 file changed, 14 insertions(+), 2 deletions(-) >> > >> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c >> b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c >> > index 3a6b2e2089f6..a3523d03d769 100644 >> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c >> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c >> > @@ -28,6 +28,7 @@ >> > #include <linux/xarray.h> >> > #include <linux/power_supply.h> >> > #include <linux/pm_runtime.h> >> > +#include <linux/sched/smt.h> >> > #include <linux/suspend.h> >> > #include <acpi/video.h> >> > #include <acpi/actbl.h> >> > @@ -1473,6 +1474,13 @@ void amdgpu_acpi_release(void) >> > */ >> > bool amdgpu_acpi_is_s3_active(struct amdgpu_device *adev) >> > { >> > +#ifdef CONFIG_X86 >> > + if (!sched_smt_active()) { >> > + dev_warn_once(adev->dev, >> > + "SMT is disabled by the BIOS.\n" >> > + "To use suspend-to-ram enable SMT in BIOS setup.\n"); >> > + } >> > +#endif >> >> Will this generate a spurious warning on platforms that are natively non-SMT? > > Yeah; it could. I'm not sure how we can reliably detect this. I thought about looking for > the 'ht' flag, but that probably wouldn't work for this case. > > Are there AMD Zen CPUs or APUs that are non-SMT? Could gate the sched_smt_active() > check to only run when it's an AMD x86 Zen SoC. > >> >> Alex >> >> > return !(adev->flags & AMD_IS_APU) || >> > (pm_suspend_target_state == PM_SUSPEND_MEM); >> > } >> > @@ -1499,16 +1507,20 @@ bool amdgpu_acpi_is_s0ix_active(struct >> amdgpu_device *adev) >> > * S0ix even though the system is suspending to idle, so return false >> > * in that case. >> > */ >> > - if (!(acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0)) >> > + if (!(acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0)) { >> > dev_warn_once(adev->dev, >> > "Power consumption will be higher as BIOS has not been >> configured for suspend-to-idle.\n" >> > "To use suspend-to-idle change the sleep mode in BIOS >> setup.\n"); >> > + return false; >> > + } >> > >> > #if !IS_ENABLED(CONFIG_AMD_PMC) >> > dev_warn_once(adev->dev, >> > "Power consumption will be higher as the kernel has not been >> compiled with CONFIG_AMD_PMC.\n"); >> > -#endif /* CONFIG_AMD_PMC */ >> > + return false; >> > +#else >> > return true; >> > +#endif /* CONFIG_AMD_PMC */ >> > } >> > >> > #endif /* CONFIG_SUSPEND */ >> > -- >> > 2.34.1 >> >
