On 26/08/2019 23:33, Rob Herring wrote:
> There's a few issues with the runtime PM initialization.
>
> The documentation states pm_runtime_set_active() should be called before
> pm_runtime_enable(). The pm_runtime_put_autosuspend() could suspend the GPU
> before panfrost_perfcnt_init() is called which touches the h/w. The
> autosuspend delay keeps things from breaking. There's no need explicitly
> power off the GPU only to wake back up with pm_runtime_get_sync(). Just
> delaying pm_runtime_enable to the end of probe is sufficient.
>
> Lets move all the runtime PM calls into the probe() function so they are
> all in one place and are done after all initialization.
>
> Cc: Tomeu Vizoso <tomeu.viz...@collabora.com>
> Cc: Steven Price <steven.pr...@arm.com>
> Cc: David Airlie <airl...@linux.ie>
> Cc: Daniel Vetter <dan...@ffwll.ch>
> Acked-by: Alyssa Rosenzweig <alyssa.rosenzw...@collabora.com>
> Signed-off-by: Rob Herring <r...@kernel.org>
Reviewed-by: Steven Price <steven.pr...@arm.com>
Steve
> ---
> v3:
> - Move autosuspend setup after pm_runtime_enable as only autosuspend changes
> trigger suspend.
> - Fix autosuspend delay to 50ms instead of 0.
>
> drivers/gpu/drm/panfrost/panfrost_device.c | 9 ---------
> drivers/gpu/drm/panfrost/panfrost_drv.c | 10 ++++++----
> 2 files changed, 6 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/gpu/drm/panfrost/panfrost_device.c
> b/drivers/gpu/drm/panfrost/panfrost_device.c
> index 4da71bb56c20..73805210834e 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_device.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_device.c
> @@ -5,7 +5,6 @@
> #include <linux/clk.h>
> #include <linux/reset.h>
> #include <linux/platform_device.h>
> -#include <linux/pm_runtime.h>
> #include <linux/regulator/consumer.h>
>
> #include "panfrost_device.h"
> @@ -166,14 +165,6 @@ int panfrost_device_init(struct panfrost_device *pfdev)
> if (err)
> goto err_out4;
>
> - /* runtime PM will wake us up later */
> - panfrost_gpu_power_off(pfdev);
> -
> - pm_runtime_set_active(pfdev->dev);
> - pm_runtime_get_sync(pfdev->dev);
> - pm_runtime_mark_last_busy(pfdev->dev);
> - pm_runtime_put_autosuspend(pfdev->dev);
> -
> err = panfrost_perfcnt_init(pfdev);
> if (err)
> goto err_out5;
> diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c
> b/drivers/gpu/drm/panfrost/panfrost_drv.c
> index d74442d71048..bc2ddeb55f5d 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_drv.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
> @@ -523,10 +523,6 @@ static int panfrost_probe(struct platform_device *pdev)
> mutex_init(&pfdev->shrinker_lock);
> INIT_LIST_HEAD(&pfdev->shrinker_list);
>
> - pm_runtime_use_autosuspend(pfdev->dev);
> - pm_runtime_set_autosuspend_delay(pfdev->dev, 50); /* ~3 frames */
> - pm_runtime_enable(pfdev->dev);
> -
> err = panfrost_device_init(pfdev);
> if (err) {
> if (err != -EPROBE_DEFER)
> @@ -541,6 +537,12 @@ static int panfrost_probe(struct platform_device *pdev)
> goto err_out1;
> }
>
> + pm_runtime_set_active(pfdev->dev);
> + pm_runtime_mark_last_busy(pfdev->dev);
> + pm_runtime_enable(pfdev->dev);
> + pm_runtime_set_autosuspend_delay(pfdev->dev, 50); /* ~3 frames */
> + pm_runtime_use_autosuspend(pfdev->dev);
> +
> /*
> * Register the DRM device with the core and the connectors with
> * sysfs
> --
> 2.20.1
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>
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