On Tue, Nov 14, 2023 at 08:22:27AM -0800, Alan Previn wrote:
> When suspending, add a timeout when calling
> intel_gt_pm_wait_for_idle else if we have a leaked
> wakeref (which would be indicative of a bug elsewhere
> in the driver), driver will at exit the suspend-resume
> cycle, after the kernel detects the held reference and
> prints a message to abort suspending instead of hanging
> in the kernel forever which then requires serial connection
> or ramoops dump to debug further.
>
> Signed-off-by: Alan Previn <alan.previn.teres.alexis@xxxxxxxxx>
> Reviewed-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
> Tested-by: Mousumi Jana <mousumi.jana@xxxxxxxxx>
could you please rebase this on top of recent drm-tip and resend?
I got a conflict while trying to apply on drm-intel-gt-next.
As I had stated in another thread, I believe we should go further
and block the suspend and have a clean return to normal operation.
But anyway, I agree this is already a good and necessary improvement
because being in the dark if some bad case like this happens is
the worst thing. So this patch is already an improvement anyway.
again:
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/gt/intel_engine_cs.c | 2 +-
> drivers/gpu/drm/i915/gt/intel_gt_pm.c | 7 ++++++-
> drivers/gpu/drm/i915/gt/intel_gt_pm.h | 7 ++++++-
> drivers/gpu/drm/i915/intel_wakeref.c | 14 ++++++++++----
> drivers/gpu/drm/i915/intel_wakeref.h | 6 ++++--
> 5 files changed, 27 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
> index 40687806d22a..ffef963037f2 100644
> --- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
> +++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
> @@ -686,7 +686,7 @@ void intel_engines_release(struct intel_gt *gt)
> if (!engine->release)
> continue;
>
> - intel_wakeref_wait_for_idle(&engine->wakeref);
> + intel_wakeref_wait_for_idle(&engine->wakeref, 0);
> GEM_BUG_ON(intel_engine_pm_is_awake(engine));
>
> engine->release(engine);
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.c b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
> index f5899d503e23..25cb39ba9fdf 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt_pm.c
> +++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
> @@ -306,6 +306,8 @@ int intel_gt_resume(struct intel_gt *gt)
>
> static void wait_for_suspend(struct intel_gt *gt)
> {
> + int final_timeout_ms = (I915_GT_SUSPEND_IDLE_TIMEOUT * 10);
> +
> if (!intel_gt_pm_is_awake(gt))
> return;
>
> @@ -318,7 +320,10 @@ static void wait_for_suspend(struct intel_gt *gt)
> intel_gt_retire_requests(gt);
> }
>
> - intel_gt_pm_wait_for_idle(gt);
> + /* we are suspending, so we shouldn't be waiting forever */
> + if (intel_gt_pm_wait_timeout_for_idle(gt, final_timeout_ms) == -ETIMEDOUT)
> + gt_warn(gt, "bailing from %s after %d milisec timeout\n",
> + __func__, final_timeout_ms);
> }
>
> void intel_gt_suspend_prepare(struct intel_gt *gt)
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.h b/drivers/gpu/drm/i915/gt/intel_gt_pm.h
> index b1eeb5b33918..1757ca4c3077 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt_pm.h
> +++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.h
> @@ -68,7 +68,12 @@ static inline void intel_gt_pm_might_put(struct intel_gt *gt)
>
> static inline int intel_gt_pm_wait_for_idle(struct intel_gt *gt)
> {
> - return intel_wakeref_wait_for_idle(>->wakeref);
> + return intel_wakeref_wait_for_idle(>->wakeref, 0);
> +}
> +
> +static inline int intel_gt_pm_wait_timeout_for_idle(struct intel_gt *gt, int timeout_ms)
> +{
> + return intel_wakeref_wait_for_idle(>->wakeref, timeout_ms);
> }
>
> void intel_gt_pm_init_early(struct intel_gt *gt);
> diff --git a/drivers/gpu/drm/i915/intel_wakeref.c b/drivers/gpu/drm/i915/intel_wakeref.c
> index 623a69089386..f2611c65246b 100644
> --- a/drivers/gpu/drm/i915/intel_wakeref.c
> +++ b/drivers/gpu/drm/i915/intel_wakeref.c
> @@ -113,14 +113,20 @@ void __intel_wakeref_init(struct intel_wakeref *wf,
> "wakeref.work", &key->work, 0);
> }
>
> -int intel_wakeref_wait_for_idle(struct intel_wakeref *wf)
> +int intel_wakeref_wait_for_idle(struct intel_wakeref *wf, int timeout_ms)
> {
> - int err;
> + int err = 0;
>
> might_sleep();
>
> - err = wait_var_event_killable(&wf->wakeref,
> - !intel_wakeref_is_active(wf));
> + if (!timeout_ms)
> + err = wait_var_event_killable(&wf->wakeref,
> + !intel_wakeref_is_active(wf));
> + else if (wait_var_event_timeout(&wf->wakeref,
> + !intel_wakeref_is_active(wf),
> + msecs_to_jiffies(timeout_ms)) < 1)
> + err = -ETIMEDOUT;
> +
> if (err)
> return err;
>
> diff --git a/drivers/gpu/drm/i915/intel_wakeref.h b/drivers/gpu/drm/i915/intel_wakeref.h
> index ec881b097368..302694a780d2 100644
> --- a/drivers/gpu/drm/i915/intel_wakeref.h
> +++ b/drivers/gpu/drm/i915/intel_wakeref.h
> @@ -251,15 +251,17 @@ __intel_wakeref_defer_park(struct intel_wakeref *wf)
> /**
> * intel_wakeref_wait_for_idle: Wait until the wakeref is idle
> * @wf: the wakeref
> + * @timeout_ms: Timeout in ms, 0 means never timeout.
> *
> * Wait for the earlier asynchronous release of the wakeref. Note
> * this will wait for any third party as well, so make sure you only wait
> * when you have control over the wakeref and trust no one else is acquiring
> * it.
> *
> - * Return: 0 on success, error code if killed.
> + * Returns 0 on success, -ETIMEDOUT upon a timeout, or the unlikely
> + * error propagation from wait_var_event_killable if timeout_ms is 0.
> */
> -int intel_wakeref_wait_for_idle(struct intel_wakeref *wf);
> +int intel_wakeref_wait_for_idle(struct intel_wakeref *wf, int timeout_ms);
>
> struct intel_wakeref_auto {
> struct drm_i915_private *i915;
>
> base-commit: 3d1e36691e73b3946b4a9ca8132a34f0319ff984
> --
> 2.39.0
>
