On Wed, Jan 25, 2023 at 1:33 PM Mario Limonciello <mario.limonciello@xxxxxxx> wrote: > > We guard the suspend entry code from running unless we have proper > BIOS support for either S3 mode or s0ix mode. > > If a user's system doesn't support either of these modes the kernel > still does offer s2idle in `/sys/power/mem_sleep` so there is an > expectation from users that it works even if the power consumption > remains very high. > > Rafael Ávila de Espíndola reports that a system of his has a > non-functional graphics stack after resuming. That system doesn't > support S3 and the FADT doesn't indicate support for low power idle. > > Through some experimentation it was concluded that even without the > hardware s0i3 support provided by the amd_pmc driver the power > consumption over suspend is decreased by running amdgpu's s0ix > suspend routine. > > The numbers over suspend showed: > * No patch: 9.2W > * Skip amdgpu suspend entirely: 10.5W > * Run amdgpu s0ix routine: 7.7W > > As this does improve the power, remove some of the guard rails in > `amdgpu_acpi.c` for only running s0ix suspend routines in the right > circumstances. > > However if this turns out to cause regressions for anyone, we should > revert this change and instead opt for skipping suspend/resume routines > entirely or try to fix the underlying behavior that makes graphics fail > after resume without underlying platform support. > > Reported-by: Rafael Ávila de Espíndola <rafael@xxxxxxxxxx> > Link: https://gitlab.freedesktop.org/drm/amd/-/issues/2364 > Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx> > --- > drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c | 8 ++------ > 1 file changed, 2 insertions(+), 6 deletions(-) > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c > index 57b5e11446c65..fa7375b97fd47 100644 > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c > @@ -1079,20 +1079,16 @@ 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; Thinking about this more, I think we may need to check the asic type here. Pre-Raven APUs didn't support S0ix at all so this may break them if they have any checks that use amdgpu_acpi_is_s0ix_active() in their code paths. Alex > - } > > #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"); > - return false; > -#else > - return true; > #endif /* CONFIG_AMD_PMC */ > + return true; > } > > #endif /* CONFIG_SUSPEND */ > -- > 2.25.1 >
