Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> writes:
> If the HW fail to ack a change in forcewake status, the machine is as
> good as dead -- it may recover, but in reality it missed the mmio
> updates and is now in a very inconsistent state. If it happens, we can't
> trust the CI results (or at least the fails may be genuine but due to
> the HW being dead and not the actual test!) so reboot the machine (CI
> checks for a kernel taint in between each test and reboots if the
> machine is tainted).
>
> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxxxxxxx>
Sounds and looks reasonable. Should we also taint if we have
unclaimed mmio after init sequence?
Reviewed-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/i915/gt/intel_reset.c | 2 +-
> drivers/gpu/drm/i915/i915_drv.h | 11 +++++++++++
> drivers/gpu/drm/i915/intel_uncore.c | 8 ++++++--
> 3 files changed, 18 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_reset.c b/drivers/gpu/drm/i915/gt/intel_reset.c
> index 419b3415370b..464369bc55ad 100644
> --- a/drivers/gpu/drm/i915/gt/intel_reset.c
> +++ b/drivers/gpu/drm/i915/gt/intel_reset.c
> @@ -1042,7 +1042,7 @@ void i915_reset(struct drm_i915_private *i915,
> * rather than continue on into oblivion. For everyone else,
> * the system should still plod along, but they have been warned!
> */
> - add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
> + add_taint_for_CI(TAINT_WARN);
> error:
> __i915_gem_set_wedged(i915);
> goto finish;
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 0a6ec61496f1..d0257808734c 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -3375,4 +3375,15 @@ static inline u32 i915_scratch_offset(const struct drm_i915_private *i915)
> return i915_ggtt_offset(i915->gt.scratch);
> }
>
> +static inline void add_taint_for_CI(unsigned int taint)
> +{
> + /*
> + * The system is "ok", just about surviving for the user, but
> + * CI results are now unreliable as the HW is very suspect.
> + * CI checks the taint state after every test and will reboot
> + * the machine if the kernel is tainted.
> + */
> + add_taint(taint, LOCKDEP_STILL_OK);
> +}
> +
> #endif
> diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
> index d1d51e1121e2..6ec1bc97b665 100644
> --- a/drivers/gpu/drm/i915/intel_uncore.c
> +++ b/drivers/gpu/drm/i915/intel_uncore.c
> @@ -111,9 +111,11 @@ wait_ack_set(const struct intel_uncore_forcewake_domain *d,
> static inline void
> fw_domain_wait_ack_clear(const struct intel_uncore_forcewake_domain *d)
> {
> - if (wait_ack_clear(d, FORCEWAKE_KERNEL))
> + if (wait_ack_clear(d, FORCEWAKE_KERNEL)) {
> DRM_ERROR("%s: timed out waiting for forcewake ack to clear.\n",
> intel_uncore_forcewake_domain_to_str(d->id));
> + add_taint_for_CI(TAINT_WARN); /* CI unreliable */
> + }
> }
>
> enum ack_type {
> @@ -186,9 +188,11 @@ fw_domain_get(const struct intel_uncore_forcewake_domain *d)
> static inline void
> fw_domain_wait_ack_set(const struct intel_uncore_forcewake_domain *d)
> {
> - if (wait_ack_set(d, FORCEWAKE_KERNEL))
> + if (wait_ack_set(d, FORCEWAKE_KERNEL)) {
> DRM_ERROR("%s: timed out waiting for forcewake ack request.\n",
> intel_uncore_forcewake_domain_to_str(d->id));
> + add_taint_for_CI(TAINT_WARN); /* CI unreliable */
> + }
> }
>
> static inline void
> --
> 2.20.1
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