On Mon, Sep 19, 2016 at 04:30:14PM +0100, Matthew Auld wrote:
> From: "arun.siluv...@linux.intel.com" <arun.siluv...@linux.intel.com>
>
> This is a preparatory patch which modifies error handler to do per engine
> hang recovery. The actual patch which implements this sequence follows
> later in the series. The aim is to prepare existing recovery function to
> adapt to this new function where applicable (which fails at this point
> because core implementation is lacking) and continue recovery using legacy
> full gpu reset.
>
> A helper function is also added to query the availability of engine
> reset.
>
> The error events behaviour that are used to notify user of reset are
> adapted to engine reset such that it doesn't break users listening to these
> events. In legacy we report an error event, a reset event before resetting
> the gpu and a reset done event marking the completion of reset. The same
> behaviour is adapted but reset event is only dispatched once even when
> multiple engines are hung. Finally once reset is complete we send reset
> done event as usual.
>
> v2
> - rework slightly
> - prefer INTEL_GEN
> - document engine_mask param
>
> Cc: Chris Wilson <ch...@chris-wilson.co.uk>
> Cc: Mika Kuoppala <mika.kuopp...@linux.intel.com>
> Signed-off-by: Ian Lister <ian.lis...@intel.com>
> Signed-off-by: Tomas Elf <tomas....@intel.com>
> Signed-off-by: Arun Siluvery <arun.siluv...@linux.intel.com>
> Signed-off-by: Matthew Auld <matthew.a...@intel.com>
> ---
> drivers/gpu/drm/i915/i915_drv.c | 26 +++++++++++++++++++
> drivers/gpu/drm/i915/i915_drv.h | 2 ++
> drivers/gpu/drm/i915/i915_irq.c | 50
> +++++++++++++++++++++++++++++++++----
> drivers/gpu/drm/i915/intel_uncore.c | 5 ++++
> 4 files changed, 78 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 7f4e8ad..99fa690 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -1804,6 +1804,32 @@ error:
> goto wakeup;
> }
>
> +/**
> + * i915_reset_engine - reset GPU engine to recover from a hang
> + * @engine: engine to reset
> + *
> + * Reset a specific GPU engine. Useful if a hang is detected.
> + * Returns zero on successful reset or otherwise an error code.
> + *
> + * Procedure is fairly simple:
> + * - force engine to idle
> + * - save current state which includes head and current request
> + * - reset engine
> + * - restore saved state and resubmit context
> + */
> +int i915_reset_engine(struct intel_engine_cs *engine)
> +{
> + int ret;
> + struct drm_i915_private *dev_priv = engine->i915;
> +
> + /* FIXME: replace me with engine reset sequence */
> + ret = -ENODEV;
> +
> + set_bit(I915_RESET_IN_PROGRESS, &dev_priv->gpu_error.flags);
> +
> + return ret;
> +}
> +
> static int i915_pm_suspend(struct device *kdev)
> {
> struct pci_dev *pdev = to_pci_dev(kdev);
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 4dd307e..79de74d 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -2888,6 +2888,8 @@ extern long i915_compat_ioctl(struct file *filp,
> unsigned int cmd,
> extern int intel_gpu_reset(struct drm_i915_private *dev_priv, u32
> engine_mask);
> extern bool intel_has_gpu_reset(struct drm_i915_private *dev_priv);
> extern void i915_reset(struct drm_i915_private *dev_priv);
> +extern bool intel_has_engine_reset(struct drm_i915_private *dev_priv);
> +extern int i915_reset_engine(struct intel_engine_cs *engine);
> extern int intel_guc_reset(struct drm_i915_private *dev_priv);
> extern void intel_engine_init_hangcheck(struct intel_engine_cs *engine);
> extern unsigned long i915_chipset_val(struct drm_i915_private *dev_priv);
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index c128fdb..45c5a26 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -2487,11 +2487,13 @@ static void i915_error_wake_up(struct
> drm_i915_private *dev_priv)
> /**
> * i915_reset_and_wakeup - do process context error handling work
> * @dev_priv: i915 device private
> + * @engine_mask: engines which are marked as hung
> *
> * Fire an error uevent so userspace can see that a hang or error
> * was detected.
> */
> -static void i915_reset_and_wakeup(struct drm_i915_private *dev_priv)
> +static void i915_reset_and_wakeup(struct drm_i915_private *dev_priv,
> + u32 engine_mask)
> {
> struct kobject *kobj = &dev_priv->drm.primary->kdev->kobj;
> char *error_event[] = { I915_ERROR_UEVENT "=1", NULL };
> @@ -2501,6 +2503,15 @@ static void i915_reset_and_wakeup(struct
> drm_i915_private *dev_priv)
> kobject_uevent_env(kobj, KOBJ_CHANGE, error_event);
>
> DRM_DEBUG_DRIVER("resetting chip\n");
> + /*
> + * This event needs to be sent before performing gpu reset. When
> + * engine resets are supported we iterate through all engines and
> + * reset hung engines individually. To keep the event dispatch
> + * mechanism consistent with full gpu reset, this is only sent once
> + * even when multiple engines are hung. It is also safe to move this
> + * here because when we are in this function, we will definitely
> + * perform gpu reset.
> + */
> kobject_uevent_env(kobj, KOBJ_CHANGE, reset_event);
>
> /*
> @@ -2511,6 +2522,28 @@ static void i915_reset_and_wakeup(struct
> drm_i915_private *dev_priv)
> * simulated reset via debugs, so get an RPM reference.
> */
> intel_runtime_pm_get(dev_priv);
> +
> + /*
> + * First attempt to reset the engines which are marked as hung. If that
> + * fails then we fallback to doing a full gpu reset.
> + */
> + if (intel_has_engine_reset(dev_priv)) {
> + struct intel_engine_cs *engine;
> + unsigned int tmp;
> + int ret = 0;
> +
> + for_each_engine_masked(engine, dev_priv, engine_mask, tmp) {
> + ret = i915_reset_engine(engine);
> + if (ret)
> + break;
> + }
> +
> + if (!ret) {
> + DRM_DEBUG_DRIVER("reset hung engines.\n");
> + goto reset_done;
> + }
> + }
> +
> intel_prepare_reset(dev_priv);
>
> do {
> @@ -2532,6 +2565,8 @@ static void i915_reset_and_wakeup(struct
> drm_i915_private *dev_priv)
> HZ));
>
> intel_finish_reset(dev_priv);
> +
> +reset_done:
> intel_runtime_pm_put(dev_priv);
>
> if (!test_bit(I915_WEDGED, &dev_priv->gpu_error.flags))
> @@ -2640,6 +2675,8 @@ static void i915_report_and_clear_eir(struct
> drm_i915_private *dev_priv)
> * i915_handle_error - handle a gpu error
> * @dev_priv: i915 device private
> * @engine_mask: mask representing engines that are hung
> + * @fmt: formatted hang msg that gets logged in captured error state
> + *
> * Do some basic checking of register state at error time and
> * dump it to the syslog. Also call i915_capture_error_state() to make
> * sure we get a record and make it available in debugfs. Fire a uevent
> @@ -2664,9 +2701,12 @@ void i915_handle_error(struct drm_i915_private
> *dev_priv,
> if (!engine_mask)
> return;
>
> - if (test_and_set_bit(I915_RESET_IN_PROGRESS,
> - &dev_priv->gpu_error.flags))
> - return;
No. This is a serialised test for a reason.
-Chris
--
Chris Wilson, Intel Open Source Technology Centre
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