[RFC 2/2] drm/amd/pm: Add support for reacting to platform profile notification

Lazar, Lijo Lijo.Lazar at amd.com
Wed Nov 10 16:05:05 UTC 2021


[Public]

I feel it's better to leave to platform vendors. For ex: for APU cases they may have implementations in which their BIOSes talk to PMFW and this might be driving something else here.

Also, not sure how to handle a case like, say a laptop with Intel CPU and AMD dgpu.

Thanks,
Lijo

________________________________
From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> on behalf of Alex Deucher <alexdeucher at gmail.com>
Sent: Wednesday, 10 November 2021, 8:44 pm
To: Limonciello, Mario
Cc: amd-gfx list
Subject: Re: [RFC 2/2] drm/amd/pm: Add support for reacting to platform profile notification

On Wed, Nov 10, 2021 at 1:24 AM Mario Limonciello
<mario.limonciello at amd.com> wrote:
>
> Various drivers provide platform profile support to let users set a hint
> in their GUI whether they want to run in a high performance, low battery
> life or balanced configuration.
>
> Drivers that provide this typically work with the firmware on their system
> to configure hardware.  In the case of AMDGPU however, the notification
> path doesn't come through firmware and can instead be provided directly
> to the driver from a notification chain.
>
> Use the information of the newly selected profile to tweak
> `dpm_force_performance_level` to that profile IFF the user hasn't manually
> selected `manual` or any other `profile_*` options.

I don't think we want to force the performance level.  This interface
forces various fixed clock configurations for debugging and profiling.
I think what we'd want to select here is the power profile (see
amdgpu_set_pp_power_profile_mode()).  For this interface you can
select various profiles (BOOTUP_DEFAULT, 3D_FULL_SCREEN, POWER_SAVING,
VIDEO, VR, COMPUTE, etc.).  These still use dynamic power management,
but they adjust the heuristics used by the GPU to select power states
so the GPU performance ramps up/down more or less aggressively.

Alex

>
> Signed-off-by: Mario Limonciello <mario.limonciello at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu.h |   3 +
>  drivers/gpu/drm/amd/pm/amdgpu_pm.c  | 105 +++++++++++++++++++++++-----
>  2 files changed, 90 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> index b85b67a88a3d..27b0be23b6ac 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> @@ -1097,6 +1097,9 @@ struct amdgpu_device {
>
>         struct amdgpu_reset_control     *reset_cntl;
>         uint32_t                        ip_versions[HW_ID_MAX][HWIP_MAX_INSTANCE];
> +
> +       /* platform profile notifications */
> +       struct notifier_block           platform_profile_notifier;
>  };
>
>  static inline struct amdgpu_device *drm_to_adev(struct drm_device *ddev)
> diff --git a/drivers/gpu/drm/amd/pm/amdgpu_pm.c b/drivers/gpu/drm/amd/pm/amdgpu_pm.c
> index 41472ed99253..33fc52b90d4c 100644
> --- a/drivers/gpu/drm/amd/pm/amdgpu_pm.c
> +++ b/drivers/gpu/drm/amd/pm/amdgpu_pm.c
> @@ -32,6 +32,7 @@
>  #include <linux/hwmon.h>
>  #include <linux/hwmon-sysfs.h>
>  #include <linux/nospec.h>
> +#include <linux/platform_profile.h>
>  #include <linux/pm_runtime.h>
>  #include <asm/processor.h>
>  #include "hwmgr.h"
> @@ -200,6 +201,33 @@ static ssize_t amdgpu_set_power_dpm_state(struct device *dev,
>         return count;
>  }
>
> +static int amdgpu_get_forced_level(struct device *dev, enum amd_dpm_forced_level *level)
> +{
> +       struct drm_device *ddev = dev_get_drvdata(dev);
> +       struct amdgpu_device *adev = drm_to_adev(ddev);
> +       int ret;
> +
> +       if (amdgpu_in_reset(adev))
> +               return -EPERM;
> +       if (adev->in_suspend && !adev->in_runpm)
> +               return -EPERM;
> +
> +       ret = pm_runtime_get_sync(ddev->dev);
> +       if (ret < 0) {
> +               pm_runtime_put_autosuspend(ddev->dev);
> +               return ret;
> +       }
> +
> +       if (adev->powerplay.pp_funcs->get_performance_level)
> +               *level = amdgpu_dpm_get_performance_level(adev);
> +       else
> +               *level = adev->pm.dpm.forced_level;
> +
> +       pm_runtime_mark_last_busy(ddev->dev);
> +       pm_runtime_put_autosuspend(ddev->dev);
> +
> +       return 0;
> +}
>
>  /**
>   * DOC: power_dpm_force_performance_level
> @@ -264,29 +292,13 @@ static ssize_t amdgpu_get_power_dpm_force_performance_level(struct device *dev,
>                                                             struct device_attribute *attr,
>                                                             char *buf)
>  {
> -       struct drm_device *ddev = dev_get_drvdata(dev);
> -       struct amdgpu_device *adev = drm_to_adev(ddev);
>         enum amd_dpm_forced_level level = 0xff;
>         int ret;
>
> -       if (amdgpu_in_reset(adev))
> -               return -EPERM;
> -       if (adev->in_suspend && !adev->in_runpm)
> -               return -EPERM;
> +       ret = amdgpu_get_forced_level(dev, &level);
>
> -       ret = pm_runtime_get_sync(ddev->dev);
> -       if (ret < 0) {
> -               pm_runtime_put_autosuspend(ddev->dev);
> +       if (ret < 0)
>                 return ret;
> -       }
> -
> -       if (adev->powerplay.pp_funcs->get_performance_level)
> -               level = amdgpu_dpm_get_performance_level(adev);
> -       else
> -               level = adev->pm.dpm.forced_level;
> -
> -       pm_runtime_mark_last_busy(ddev->dev);
> -       pm_runtime_put_autosuspend(ddev->dev);
>
>         return sysfs_emit(buf, "%s\n",
>                           (level == AMD_DPM_FORCED_LEVEL_AUTO) ? "auto" :
> @@ -405,6 +417,59 @@ static ssize_t amdgpu_set_power_dpm_force_performance_level(struct device *dev,
>         return count;
>  }
>
> +static void amdgpu_update_profile(struct device *dev, enum platform_profile_option *profile)
> +{
> +       enum amd_dpm_forced_level level;
> +       const char *str;
> +       int ret;
> +
> +       ret = amdgpu_get_forced_level(dev, &level);
> +       if (ret < 0)
> +               return;
> +
> +       /* only update profile if we're in fixed modes right now that need updating */
> +       switch (level) {
> +       case AMD_DPM_FORCED_LEVEL_LOW:
> +               if (*profile < PLATFORM_PROFILE_BALANCED)
> +                       return;
> +               break;
> +       case AMD_DPM_FORCED_LEVEL_HIGH:
> +               if (*profile > PLATFORM_PROFILE_BALANCED)
> +                       return;
> +               break;
> +       case AMD_DPM_FORCED_LEVEL_AUTO:
> +               if (*profile == PLATFORM_PROFILE_BALANCED)
> +                       return;
> +               break;
> +       default:
> +               dev_dbg(dev, "refusing to update amdgpu profile from %d\n", level);
> +               return;
> +       }
> +       if (*profile > PLATFORM_PROFILE_BALANCED)
> +               str = "high";
> +       else if (*profile < PLATFORM_PROFILE_BALANCED)
> +               str = "low";
> +       else
> +               str = "auto";
> +
> +       dev_dbg(dev, "updating platform profile to %s\n", str);
> +       amdgpu_set_power_dpm_force_performance_level(dev, NULL, str, 0);
> +}
> +
> +static int amdgpu_platform_profile_notifier_call(struct notifier_block *nb,
> +                                                 unsigned long action, void *data)
> +{
> +       if (action == PLATFORM_PROFILE_CHANGED) {
> +               enum platform_profile_option *profile = data;
> +               struct amdgpu_device *adev;
> +
> +               adev = container_of(nb, struct amdgpu_device, platform_profile_notifier);
> +               amdgpu_update_profile(adev->dev, profile);
> +       }
> +
> +       return NOTIFY_OK;
> +}
> +
>  static ssize_t amdgpu_get_pp_num_states(struct device *dev,
>                 struct device_attribute *attr,
>                 char *buf)
> @@ -3506,6 +3571,9 @@ int amdgpu_pm_sysfs_init(struct amdgpu_device *adev)
>         if (ret)
>                 return ret;
>
> +       adev->platform_profile_notifier.notifier_call = amdgpu_platform_profile_notifier_call;
> +       platform_profile_register_notifier(&adev->platform_profile_notifier);
> +
>         adev->pm.sysfs_initialized = true;
>
>         return 0;
> @@ -3519,6 +3587,7 @@ void amdgpu_pm_sysfs_fini(struct amdgpu_device *adev)
>         if (adev->pm.int_hwmon_dev)
>                 hwmon_device_unregister(adev->pm.int_hwmon_dev);
>
> +       platform_profile_unregister_notifier(&adev->platform_profile_notifier);
>         amdgpu_device_attr_remove_groups(adev, &adev->pm.pm_attr_list);
>  }
>
> --
> 2.25.1
>

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