Thank you for your contribution! Sashiko AI review found 3 potential issue(s) to consider: - [High] drm/amdgpu: runtime PM reference leak in amdgpu_pm_acpi_event_handler() - [High] drm/amdgpu: negative return treated as active in amdgpu_pm_acpi_event_handler() - [Medium] drm/amdgpu: missed SMU AC/DC update in amdgpu_pm_acpi_event_handler() during resume --
commit 5f8266206967cf1a10c12c800fc318910f1e455a Author: Andre Eikmeyer <[email protected]> drm/amdgpu: Skip AC/DC notification while the GPU is runtime suspended This commit updates amdgpu_pm_acpi_event_handler() to check if a GMUX GPU is runtime active via pm_runtime_get_if_active() before sending AC/DC power source notifications to the SMU. When the GPU is suspended, it records the updated power state in adev->pm.ac_power so it can be applied upon resume. > diff --git a/drivers/gpu/drm/amd/pm/amdgpu_dpm.c > b/drivers/gpu/drm/amd/pm/amdgpu_dpm.c > index 808be6c425bff..b64f0b681fe1a 100644 > --- a/drivers/gpu/drm/amd/pm/amdgpu_dpm.c > +++ b/drivers/gpu/drm/amd/pm/amdgpu_dpm.c [ ... ] > @@ -498,20 +499,26 @@ int amdgpu_dpm_smu_i2c_bus_access(struct amdgpu_device > *adev, > > void amdgpu_pm_acpi_event_handler(struct amdgpu_device *adev) > { > + int active = 0; > + > if (adev->pm.dpm_enabled) { > mutex_lock(&adev->pm.mutex); > + active = adev->pm.rpm_mode == AMDGPU_RUNPM_GMUX ? > + pm_runtime_get_if_active(adev->dev) : 1; [Severity: Medium] Can an AC/DC notification be missed if an ACPI event races with runtime resume? During rpm_resume() -> amdgpu_pmops_runtime_resume() -> amdgpu_device_resume(), dev->power.runtime_status remains RPM_RESUMING until amdgpu_pmops_runtime_resume() returns. Inside amdgpu_device_resume(), adev->pm.ac_power is consumed without holding adev->pm.mutex during amdgpu_device_ip_resume() -> pp_resume() -> hwmgr_resume() on PowerPlay GPUs and during amdgpu_device_ip_late_init() -> smu_late_init() on swsmu GPUs: drivers/gpu/drm/amd/amdgpu/amdgpu_device.c:amdgpu_device_resume() { ... r = amdgpu_device_ip_resume(adev); ... r = amdgpu_device_ip_late_init(adev); if (r) goto exit; queue_delayed_work(system_dfl_wq, &adev->delayed_init_work, msecs_to_jiffies(AMDGPU_RESUME_MS)); exit: ... /* Make sure IB tests flushed */ flush_delayed_work(&adev->delayed_init_work); } If amdgpu_pm_acpi_event_handler() runs after IP resume/late_init has already applied the power state, while flush_delayed_work() or the remainder of amdgpu_pmops_runtime_resume() is still executing, pm_runtime_get_if_active() sees runtime_status == RPM_RESUMING and returns 0. Would that cause the handler to skip notifying the SMU after the resume path has already passed the point where adev->pm.ac_power is applied, leaving the GPU with stale AC/DC limits? > + > if (power_supply_is_system_supplied() > 0) > adev->pm.ac_power = true; > else > adev->pm.ac_power = false; > > - if (adev->powerplay.pp_funcs && > - adev->powerplay.pp_funcs->notify_ac_dc) > - amdgpu_dpm_notify_ac_dc(adev); > - > - if (is_support_sw_smu(adev)) > - smu_set_ac_dc(adev->powerplay.pp_handle, true); > + if (active) { [Severity: High] Should this check be (active > 0) instead of (active)? pm_runtime_get_if_active() returns 1 when the device is active, 0 when it is not active, and -EINVAL without incrementing dev->power.usage_count when runtime PM is disabled (dev->power.disable_depth > 0 or !CONFIG_PM). On GMUX systems, amdgpu_pci_probe() sets DPM_FLAG_SMART_PREPARE | DPM_FLAG_SMART_SUSPEND | DPM_FLAG_MAY_SKIP_RESUME, which allows a runtime-suspended GMUX GPU (powered off, with adev->pm.dpm_enabled still true on PowerPlay GPUs) to remain suspended across system sleep while the PM core increments dev->power.disable_depth during __device_suspend_late() through dpm_resume_early(). If an ACPI AC/DC event runs while disable_depth > 0, active will be -EINVAL and if (active) will evaluate to true, calling amdgpu_dpm_notify_ac_dc() or smu_set_ac_dc() without a runtime PM reference while the GPU may be powered off. > + if (adev->powerplay.pp_funcs && > + adev->powerplay.pp_funcs->notify_ac_dc) > + amdgpu_dpm_notify_ac_dc(adev); > > + if (is_support_sw_smu(adev)) > + smu_set_ac_dc(adev->powerplay.pp_handle, true); > + } [Severity: High] Does amdgpu_pm_acpi_event_handler() leak the runtime PM usage reference on adev->dev when the GPU is active? When adev->pm.rpm_mode == AMDGPU_RUNPM_GMUX and the GPU is in the RPM_ACTIVE state, pm_runtime_get_if_active(adev->dev) increments dev->power.usage_count and returns 1. Because there is no matching pm_runtime_put_autosuspend() or pm_runtime_put() call after notifying the SMU, won't each ACPI AC/DC event while the GPU is active permanently leak a runtime PM reference and prevent the GPU from runtime suspending again? -- Sashiko AI review ยท https://sashiko.dev/#/patchset/[email protected]?part=12
