Re: [PATCH v4 05/13] drm/panfrost: Move all device power up and down into RPM callbacks
From: Steven Price
Date: Thu Jul 30 2026 - 07:14:02 EST
On 29/07/2026 03:54, Adrián Larumbe wrote:
> During device probe(), failure to do a PM get() will leave the usage_count
> set to 0, which is the value assigned at device creation time. That means
> when the autosuspend delay expires, runtime suspend callback won't be
> invoked, so the device will remain powered on forever.
>
> On top of that, failure to call PM put() during device unplug means
> Panfrost device's PM usage_count increases monotonically for every new
> module reload.
>
> The combined outcome of both of the above was that devfreq OPP transition
> notifications would be printed all the time, even when no jobs are being
> submitted. This quickly fills the kernel ring buffer with junk.
>
> Even direr than that was the fact MMU interrupts are only enabled when
> the device is reset, so after device probe() the very first job targeting
> the tiler heap BO would always time out, because the driver's PM runtime
> resume callback would not be invoked.
>
> Fix all that by moving all GPU enabling and disabling into RPM resume and
> suspend callbacks, and making sure we resume the device right before
> touching any HW registers. This is done in imitation of the Panthor model.
>
> Signed-off-by: Adrián Larumbe <adrian.larumbe@xxxxxxxxxxxxx>
> Fixes: 635430797d3f ("drm/panfrost: Rework runtime PM initialization")
> Fixes: 876b15d2c88d ("drm/panfrost: Fix module unload")
> ---
> drivers/gpu/drm/panfrost/panfrost_device.c | 375 +++++++++++++++++------------
> drivers/gpu/drm/panfrost/panfrost_device.h | 9 +
> drivers/gpu/drm/panfrost/panfrost_drv.c | 10 +-
> drivers/gpu/drm/panfrost/panfrost_gpu.c | 7 +-
> drivers/gpu/drm/panfrost/panfrost_job.c | 7 +-
> 5 files changed, 237 insertions(+), 171 deletions(-)
>
> diff --git a/drivers/gpu/drm/panfrost/panfrost_device.c b/drivers/gpu/drm/panfrost/panfrost_device.c
> index 03905495aee2..a9d29d9ee22b 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_device.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_device.c
> @@ -34,6 +34,40 @@ static void panfrost_reset_fini(struct panfrost_device *pfdev)
> reset_control_assert(pfdev->rstc);
> }
>
> +static int panfrost_clk_enable(struct panfrost_device *pfdev)
> +{
> + int err;
> +
> + err = clk_enable(pfdev->clock);
> + if (err)
> + return err;
> +
> + err = clk_enable(pfdev->bus_clock);
> + if (err)
> + goto disable_clock;
> +
> + err = clk_enable(pfdev->bus_ace_clock);
> + if (err)
> + goto disable_bus_clock;
> +
> + return 0;
> +
> +disable_bus_clock:
> + clk_disable(pfdev->bus_clock);
> +disable_clock:
> + clk_disable(pfdev->clock);
> +
> + return err;
> +}
> +
> +static void panfrost_clk_disable(struct panfrost_device *pfdev)
> +{
> + clk_disable(pfdev->bus_ace_clock);
> + clk_disable(pfdev->bus_clock);
> + clk_disable(pfdev->clock);
> + reset_control_assert(pfdev->rstc);
> +}
> +
> static int panfrost_clk_init(struct panfrost_device *pfdev)
> {
> int err;
> @@ -48,7 +82,7 @@ static int panfrost_clk_init(struct panfrost_device *pfdev)
> rate = clk_get_rate(pfdev->clock);
> dev_info(pfdev->base.dev, "clock rate = %lu\n", rate);
>
> - err = clk_prepare_enable(pfdev->clock);
> + err = clk_prepare(pfdev->clock);
> if (err)
> return err;
>
> @@ -57,44 +91,55 @@ static int panfrost_clk_init(struct panfrost_device *pfdev)
> dev_err(pfdev->base.dev, "get bus_clock failed %ld\n",
> PTR_ERR(pfdev->bus_clock));
> err = PTR_ERR(pfdev->bus_clock);
> - goto disable_clock;
> + goto unprepare_clock;
> }
>
> if (pfdev->bus_clock) {
> rate = clk_get_rate(pfdev->bus_clock);
> dev_info(pfdev->base.dev, "bus_clock rate = %lu\n", rate);
>
> - err = clk_prepare_enable(pfdev->bus_clock);
> + err = clk_prepare(pfdev->bus_clock);
> if (err)
> - goto disable_clock;
> + goto unprepare_clock;
> }
>
> pfdev->bus_ace_clock = devm_clk_get_optional(pfdev->base.dev, "bus_ace");
> if (IS_ERR(pfdev->bus_ace_clock)) {
> err = PTR_ERR(pfdev->bus_ace_clock);
> dev_err(pfdev->base.dev, "get bus_ace_clock failed %d\n", err);
> - goto disable_bus_clock;
> + goto unprepare_bus_clock;
> }
>
> - err = clk_prepare_enable(pfdev->bus_ace_clock);
> + err = clk_prepare(pfdev->bus_ace_clock);
> if (err)
> - goto disable_bus_clock;
> + goto unprepare_bus_clock;
> +
> + if (!(pfdev->comp->pm_features & BIT(GPU_PM_RT))) {
> + err = panfrost_clk_enable(pfdev);
> + if (err)
> + goto unprepare_bus_ace_clock;
> + }
>
> return 0;
>
> -disable_bus_clock:
> - clk_disable_unprepare(pfdev->bus_clock);
> -disable_clock:
> - clk_disable_unprepare(pfdev->clock);
> +unprepare_bus_ace_clock:
> + clk_unprepare(pfdev->bus_ace_clock);
> +unprepare_bus_clock:
> + clk_unprepare(pfdev->bus_clock);
> +unprepare_clock:
> + clk_unprepare(pfdev->clock);
>
> return err;
> }
>
> static void panfrost_clk_fini(struct panfrost_device *pfdev)
> {
> - clk_disable_unprepare(pfdev->bus_ace_clock);
> - clk_disable_unprepare(pfdev->bus_clock);
> - clk_disable_unprepare(pfdev->clock);
> + if (!(pfdev->comp->pm_features & BIT(GPU_PM_RT)))
> + panfrost_clk_disable(pfdev);
> +
> + clk_unprepare(pfdev->bus_ace_clock);
> + clk_unprepare(pfdev->bus_clock);
> + clk_unprepare(pfdev->clock);
> }
>
> static int panfrost_regulator_init(struct panfrost_device *pfdev)
> @@ -212,6 +257,133 @@ static int panfrost_pm_domain_init(struct panfrost_device *pfdev)
> return err;
> }
>
> +static int panfrost_device_runtime_resume(struct device *dev)
> +{
> + struct panfrost_device *pfdev = dev_get_drvdata(dev);
> + int ret;
> +
> + if (pfdev->comp->pm_features & BIT(GPU_PM_RT)) {
> + ret = reset_control_deassert(pfdev->rstc);
> + if (ret)
> + return ret;
> +
> + ret = panfrost_clk_enable(pfdev);
> + if (ret)
> + goto err_clk;
> + }
> +
> + panfrost_device_reset(pfdev, true);
> + panfrost_devfreq_resume(pfdev);
> +
> + return 0;
> +
> +err_clk:
> + if (pfdev->comp->pm_features & BIT(GPU_PM_RT))
> + reset_control_assert(pfdev->rstc);
> + return ret;
> +}
> +
> +static int panfrost_device_runtime_suspend(struct device *dev)
> +{
> + struct panfrost_device *pfdev = dev_get_drvdata(dev);
> +
> + if (!panfrost_jm_is_idle(pfdev))
> + return -EBUSY;
> +
> + panfrost_devfreq_suspend(pfdev);
> + panfrost_jm_suspend_irq(pfdev);
> + panfrost_mmu_suspend_irq(pfdev);
> + panfrost_gpu_suspend_irq(pfdev);
> + panfrost_gpu_power_off(pfdev);
> +
> + if (pfdev->comp->pm_features & BIT(GPU_PM_RT))
> + panfrost_clk_disable(pfdev);
> +
> + return 0;
> +}
> +
> +static int panfrost_device_resume(struct device *dev)
> +{
> + struct panfrost_device *pfdev = dev_get_drvdata(dev);
> + int ret;
> +
> + if (pfdev->comp->pm_features & BIT(GPU_PM_VREG_OFF)) {
> + unsigned long freq = pfdev->pfdevfreq.fast_rate;
> + struct dev_pm_opp *opp;
> +
> + opp = dev_pm_opp_find_freq_ceil(dev, &freq);
> + if (IS_ERR(opp))
> + return PTR_ERR(opp);
> + dev_pm_opp_set_opp(dev, opp);
> + dev_pm_opp_put(opp);
> + }
> +
> + if (pfdev->comp->pm_features & BIT(GPU_PM_CLK_DIS)) {
> + ret = clk_enable(pfdev->clock);
> + if (ret)
> + goto err_clk;
> +
> + if (pfdev->bus_clock) {
> + ret = clk_enable(pfdev->bus_clock);
> + if (ret)
> + goto err_bus_clk;
> + }
> + }
> +
> + ret = pm_runtime_force_resume(dev);
> + if (ret)
> + goto err_resume;
> +
> + return 0;
> +
> +err_resume:
> + if (pfdev->comp->pm_features & BIT(GPU_PM_CLK_DIS) && pfdev->bus_clock)
> + clk_disable(pfdev->bus_clock);
> +err_bus_clk:
> + if (pfdev->comp->pm_features & BIT(GPU_PM_CLK_DIS))
> + clk_disable(pfdev->clock);
> +err_clk:
> + if (pfdev->comp->pm_features & BIT(GPU_PM_VREG_OFF))
> + dev_pm_opp_set_opp(dev, NULL);
> + return ret;
> +}
> +
> +static int panfrost_device_suspend(struct device *dev)
> +{
> + struct panfrost_device *pfdev = dev_get_drvdata(dev);
> + int ret;
> +
> + ret = pm_runtime_force_suspend(dev);
> + if (ret)
> + return ret;
> +
> + if (pfdev->comp->pm_features & BIT(GPU_PM_CLK_DIS)) {
> + if (pfdev->bus_clock)
> + clk_disable(pfdev->bus_clock);
> +
> + clk_disable(pfdev->clock);
> + }
> +
> + if (pfdev->comp->pm_features & BIT(GPU_PM_VREG_OFF))
> + dev_pm_opp_set_opp(dev, NULL);
> +
> + return 0;
> +}
> +
> +EXPORT_GPL_DEV_PM_OPS(panfrost_pm_ops) = {
> + RUNTIME_PM_OPS(panfrost_device_runtime_suspend, panfrost_device_runtime_resume, NULL)
> + SYSTEM_SLEEP_PM_OPS(panfrost_device_suspend, panfrost_device_resume)
> +};
> +
> +void panfrost_try_suspend_device(struct panfrost_device *pfdev)
> +{
> + pm_runtime_put_sync_suspend(pfdev->base.dev);
> +
> + /* If PM is disabled, we need to call the suspend handler manually. */
> + if (!IS_ENABLED(CONFIG_PM))
> + panfrost_device_runtime_suspend(pfdev->base.dev);
> +}
> +
> int panfrost_device_init(struct panfrost_device *pfdev)
> {
> int err;
> @@ -265,10 +437,25 @@ int panfrost_device_init(struct panfrost_device *pfdev)
> goto out_regulator;
> }
>
> - err = panfrost_gpu_init(pfdev);
> + err = devm_pm_runtime_enable(pfdev->base.dev);
> if (err)
> goto out_regulator;
>
> + err = pm_runtime_resume_and_get(pfdev->base.dev);
> + if (err)
> + goto out_regulator;
> +
> + /* If PM is disabled, we need to call panfrost_device_runtime_resume() manually. */
> + if (!IS_ENABLED(CONFIG_PM)) {
> + err = panfrost_device_runtime_resume(pfdev->base.dev);
> + if (err)
> + goto out_regulator;
> + }
> +
> + err = panfrost_gpu_init(pfdev);
We need the call to panfrost_gpu_init_features() (made by
panfrost_gpu_init()) before powering up the GPU with
panfrost_gpu_power_on() (which will now be getting called by the RPM
callbacks). I think what you've got will attempt to power up the GPU
with no cores (because the core masks haven't yet been discovered).
Things will probably work because a suspend/resume cycle afterwards will
'fix' things, but this relies on that suspend/resume cycle happening.
Thanks,
Steve
> + if (err)
> + goto out_rpm_put;
> +
> err = panfrost_mmu_init(pfdev);
> if (err)
> goto out_gpu;
> @@ -295,6 +482,8 @@ int panfrost_device_init(struct panfrost_device *pfdev)
> panfrost_mmu_fini(pfdev);
> out_gpu:
> panfrost_gpu_fini(pfdev);
> +out_rpm_put:
> + panfrost_try_suspend_device(pfdev);
> out_regulator:
> panfrost_regulator_fini(pfdev);
> out_devfreq:
> @@ -313,12 +502,10 @@ void panfrost_device_fini(struct panfrost_device *pfdev)
> panfrost_gem_shrinker_fini(pfdev);
> panfrost_perfcnt_fini(pfdev);
> panfrost_jm_fini(pfdev);
> - panfrost_mmu_fini(pfdev);
> - panfrost_gpu_fini(pfdev);
> - panfrost_devfreq_fini(pfdev);
> + panfrost_try_suspend_device(pfdev);
> panfrost_regulator_fini(pfdev);
> + panfrost_devfreq_fini(pfdev);
> panfrost_clk_fini(pfdev);
> - panfrost_reset_fini(pfdev);
> panfrost_pm_domain_fini(pfdev);
> }
>
> @@ -424,148 +611,20 @@ bool panfrost_exception_needs_reset(const struct panfrost_device *pfdev,
>
> void panfrost_device_reset(struct panfrost_device *pfdev, bool enable_job_int)
> {
> - panfrost_gpu_soft_reset(pfdev);
> -
> - panfrost_gpu_power_on(pfdev);
> - panfrost_mmu_reset(pfdev);
> -
> - panfrost_jm_reset_interrupts(pfdev);
> - if (enable_job_int)
> - panfrost_jm_enable_interrupts(pfdev);
> -}
> -
> -static int panfrost_device_runtime_resume(struct device *dev)
> -{
> - struct panfrost_device *pfdev = dev_get_drvdata(dev);
> - int ret;
> -
> - if (pfdev->comp->pm_features & BIT(GPU_PM_RT)) {
> - ret = reset_control_deassert(pfdev->rstc);
> - if (ret)
> - return ret;
> -
> - ret = clk_enable(pfdev->clock);
> - if (ret)
> - goto err_clk;
> -
> - ret = clk_enable(pfdev->bus_clock);
> - if (ret)
> - goto err_bus_clk;
> -
> - ret = clk_enable(pfdev->bus_ace_clock);
> - if (ret)
> - goto err_bus_ace_clk;
> - }
> -
> - panfrost_device_reset(pfdev, true);
> - panfrost_devfreq_resume(pfdev);
> -
> - return 0;
> -
> -err_bus_ace_clk:
> - if (pfdev->comp->pm_features & BIT(GPU_PM_RT))
> - clk_disable(pfdev->bus_clock);
> -err_bus_clk:
> - if (pfdev->comp->pm_features & BIT(GPU_PM_RT))
> - clk_disable(pfdev->clock);
> -err_clk:
> - if (pfdev->comp->pm_features & BIT(GPU_PM_RT))
> - reset_control_assert(pfdev->rstc);
> - return ret;
> -}
> -
> -static int panfrost_device_runtime_suspend(struct device *dev)
> -{
> - struct panfrost_device *pfdev = dev_get_drvdata(dev);
> -
> - if (!panfrost_jm_is_idle(pfdev))
> - return -EBUSY;
> -
> - panfrost_devfreq_suspend(pfdev);
> - panfrost_jm_suspend_irq(pfdev);
> - panfrost_mmu_suspend_irq(pfdev);
> - panfrost_gpu_suspend_irq(pfdev);
> - panfrost_gpu_power_off(pfdev);
> -
> - if (pfdev->comp->pm_features & BIT(GPU_PM_RT)) {
> - clk_disable(pfdev->bus_ace_clock);
> - clk_disable(pfdev->bus_clock);
> - clk_disable(pfdev->clock);
> - reset_control_assert(pfdev->rstc);
> - }
> -
> - return 0;
> -}
> -
> -static int panfrost_device_resume(struct device *dev)
> -{
> - struct panfrost_device *pfdev = dev_get_drvdata(dev);
> - int ret;
> -
> - if (pfdev->comp->pm_features & BIT(GPU_PM_VREG_OFF)) {
> - unsigned long freq = pfdev->pfdevfreq.fast_rate;
> - struct dev_pm_opp *opp;
> -
> - opp = dev_pm_opp_find_freq_ceil(dev, &freq);
> - if (IS_ERR(opp))
> - return PTR_ERR(opp);
> - dev_pm_opp_set_opp(dev, opp);
> - dev_pm_opp_put(opp);
> - }
> -
> - if (pfdev->comp->pm_features & BIT(GPU_PM_CLK_DIS)) {
> - ret = clk_enable(pfdev->clock);
> - if (ret)
> - goto err_clk;
> -
> - if (pfdev->bus_clock) {
> - ret = clk_enable(pfdev->bus_clock);
> - if (ret)
> - goto err_bus_clk;
> - }
> - }
> -
> - ret = pm_runtime_force_resume(dev);
> - if (ret)
> - goto err_resume;
> -
> - return 0;
> -
> -err_resume:
> - if (pfdev->comp->pm_features & BIT(GPU_PM_CLK_DIS) && pfdev->bus_clock)
> - clk_disable(pfdev->bus_clock);
> -err_bus_clk:
> - if (pfdev->comp->pm_features & BIT(GPU_PM_CLK_DIS))
> - clk_disable(pfdev->clock);
> -err_clk:
> - if (pfdev->comp->pm_features & BIT(GPU_PM_VREG_OFF))
> - dev_pm_opp_set_opp(dev, NULL);
> - return ret;
> -}
> -
> -static int panfrost_device_suspend(struct device *dev)
> -{
> - struct panfrost_device *pfdev = dev_get_drvdata(dev);
> int ret;
>
> - ret = pm_runtime_force_suspend(dev);
> - if (ret)
> - return ret;
> -
> - if (pfdev->comp->pm_features & BIT(GPU_PM_CLK_DIS)) {
> - if (pfdev->bus_clock)
> - clk_disable(pfdev->bus_clock);
> + /* Do the actual device reset */
> + ret = panfrost_gpu_soft_reset(pfdev);
> + panfrost_gpu_power_on(pfdev);
>
> - clk_disable(pfdev->clock);
> + /* Post-reset */
> + if (panfrost_device_started(pfdev)) {
> + panfrost_mmu_reset(pfdev);
> + panfrost_jm_reset_interrupts(pfdev);
> + if (enable_job_int)
> + panfrost_jm_enable_interrupts(pfdev);
> }
>
> - if (pfdev->comp->pm_features & BIT(GPU_PM_VREG_OFF))
> - dev_pm_opp_set_opp(dev, NULL);
> -
> - return 0;
> + if (!panfrost_device_started(pfdev) && !ret)
> + pfdev->gpu_started = true;
> }
> -
> -EXPORT_GPL_DEV_PM_OPS(panfrost_pm_ops) = {
> - RUNTIME_PM_OPS(panfrost_device_runtime_suspend, panfrost_device_runtime_resume, NULL)
> - SYSTEM_SLEEP_PM_OPS(panfrost_device_suspend, panfrost_device_resume)
> -};
> diff --git a/drivers/gpu/drm/panfrost/panfrost_device.h b/drivers/gpu/drm/panfrost/panfrost_device.h
> index ec55c136b1b6..eeca57efcbec 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_device.h
> +++ b/drivers/gpu/drm/panfrost/panfrost_device.h
> @@ -142,6 +142,7 @@ struct panfrost_device {
> /* pm_domains for devices with more than one. */
> struct device *pm_domain_devs[MAX_PM_DOMAINS];
> struct device_link *pm_domain_links[MAX_PM_DOMAINS];
> + bool gpu_started;
> bool coherent;
>
> struct panfrost_features features;
> @@ -253,6 +254,8 @@ int panfrost_device_init(struct panfrost_device *pfdev);
> void panfrost_device_fini(struct panfrost_device *pfdev);
> void panfrost_device_reset(struct panfrost_device *pfdev, bool enable_job_int);
>
> +void panfrost_try_suspend_device(struct panfrost_device *pfdev);
> +
> extern const struct dev_pm_ops panfrost_pm_ops;
>
> enum drm_panfrost_exception_type {
> @@ -342,4 +345,10 @@ panfrost_device_schedule_reset(struct panfrost_device *pfdev)
> queue_work(pfdev->reset.wq, &pfdev->reset.work);
> }
>
> +static inline bool
> +panfrost_device_started(struct panfrost_device *pfdev)
> +{
> + return pfdev->gpu_started;
> +}
> +
> #endif
> diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c
> index 331a3bd5b98c..27f4c4b217f5 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_drv.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
> @@ -988,9 +988,7 @@ static int panfrost_probe(struct platform_device *pdev)
> goto err_out0;
> }
>
> - pm_runtime_set_active(pfdev->base.dev);
> pm_runtime_mark_last_busy(pfdev->base.dev);
> - pm_runtime_enable(pfdev->base.dev);
> pm_runtime_set_autosuspend_delay(pfdev->base.dev, 50); /* ~3 frames */
> pm_runtime_use_autosuspend(pfdev->base.dev);
>
> @@ -1002,13 +1000,12 @@ static int panfrost_probe(struct platform_device *pdev)
> if (err < 0)
> goto err_out1;
>
> + pm_runtime_put_autosuspend(pfdev->base.dev);
>
> return 0;
>
> err_out1:
> - pm_runtime_disable(pfdev->base.dev);
> panfrost_device_fini(pfdev);
> - pm_runtime_set_suspended(pfdev->base.dev);
> err_out0:
> return err;
> }
> @@ -1019,10 +1016,9 @@ static void panfrost_remove(struct platform_device *pdev)
>
> drm_dev_unregister(&pfdev->base);
>
> - pm_runtime_get_sync(pfdev->base.dev);
> - pm_runtime_disable(pfdev->base.dev);
> + drm_WARN_ON(&pfdev->base, pm_runtime_get_sync(pfdev->base.dev) < 0);
> +
> panfrost_device_fini(pfdev);
> - pm_runtime_set_suspended(pfdev->base.dev);
> }
>
> static ssize_t profiling_show(struct device *dev,
> diff --git a/drivers/gpu/drm/panfrost/panfrost_gpu.c b/drivers/gpu/drm/panfrost/panfrost_gpu.c
> index 7d555e63e21a..416964282138 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_gpu.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_gpu.c
> @@ -516,9 +516,8 @@ int panfrost_gpu_init(struct panfrost_device *pfdev)
> {
> int err;
>
> - err = panfrost_gpu_soft_reset(pfdev);
> - if (err)
> - return err;
> + if (!panfrost_device_started(pfdev))
> + return -ETIMEDOUT;
>
> err = panfrost_gpu_init_features(pfdev);
> if (err)
> @@ -543,8 +542,6 @@ int panfrost_gpu_init(struct panfrost_device *pfdev)
> return err;
> }
>
> - panfrost_gpu_power_on(pfdev);
> -
> return 0;
> }
>
> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
> index 2d12b83e900a..35ff5b0f0013 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_job.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
> @@ -446,7 +446,9 @@ void panfrost_jm_suspend_irq(struct panfrost_device *pfdev)
> set_bit(PANFROST_COMP_BIT_JOB, pfdev->is_suspended);
>
> job_write(pfdev, JOB_INT_MASK, 0);
> - synchronize_irq(pfdev->js->irq);
> +
> + if (pfdev->js)
> + synchronize_irq(pfdev->js->irq);
> }
>
> static void panfrost_job_handle_err(struct panfrost_device *pfdev,
> @@ -971,6 +973,9 @@ int panfrost_jm_is_idle(struct panfrost_device *pfdev)
> struct panfrost_job_slot *js = pfdev->js;
> int i;
>
> + if (!js)
> + return true;
> +
> for (i = 0; i < NUM_JOB_SLOTS; i++) {
> /* If there are any jobs in the HW queue, we're not idle */
> if (atomic_read(&js->queue[i].sched.credit_count))
>