Chris Wilson <[email protected]> writes:

> Upon a GPU reset, we copy the default context image over top of the
> guilty image. This will rollback the CTX_TIMESTAMP register to before
> our value of ce->runtime.last. Reset both back to 0 so that we do not
> encounter an underflow on the next schedule out after resume.
>
> This should not be a huge issue in practice, as hangs should be rare in
> correct code.
>
> Signed-off-by: Chris Wilson <[email protected]>
> Cc: Tvrtko Ursulin <[email protected]>

Reviewed-by: Mika Kuoppala <[email protected]>

> ---
>  drivers/gpu/drm/i915/gt/intel_lrc.c | 24 +++++++++++++-----------
>  1 file changed, 13 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c 
> b/drivers/gpu/drm/i915/gt/intel_lrc.c
> index 9104796673dc..d53078b345be 100644
> --- a/drivers/gpu/drm/i915/gt/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
> @@ -238,6 +238,17 @@ __execlists_update_reg_state(const struct intel_context 
> *ce,
>                            const struct intel_engine_cs *engine,
>                            u32 head);
>  
> +static u32 intel_context_get_runtime(const struct intel_context *ce)
> +{
> +     /*
> +      * We can use either ppHWSP[16] which is recorded before the context
> +      * switch (and so excludes the cost of context switches) or use the
> +      * value from the context image itself, which is saved/restored earlier
> +      * and so includes the cost of the save.
> +      */
> +     return READ_ONCE(ce->lrc_reg_state[CTX_TIMESTAMP]);
> +}
> +
>  static void mark_eio(struct i915_request *rq)
>  {
>       if (i915_request_completed(rq))
> @@ -1154,6 +1165,7 @@ static void restore_default_state(struct intel_context 
> *ce,
>                      engine->context_size - PAGE_SIZE);
>  
>       execlists_init_reg_state(regs, ce, engine, ce->ring, false);
> +     ce->runtime.last = intel_context_get_runtime(ce);
>  }
>  
>  static void reset_active(struct i915_request *rq,
> @@ -1195,17 +1207,6 @@ static void reset_active(struct i915_request *rq,
>       ce->lrc_desc |= CTX_DESC_FORCE_RESTORE;
>  }
>  
> -static u32 intel_context_get_runtime(const struct intel_context *ce)
> -{
> -     /*
> -      * We can use either ppHWSP[16] which is recorded before the context
> -      * switch (and so excludes the cost of context switches) or use the
> -      * value from the context image itself, which is saved/restored earlier
> -      * and so includes the cost of the save.
> -      */
> -     return READ_ONCE(ce->lrc_reg_state[CTX_TIMESTAMP]);
> -}
> -
>  static void st_update_runtime_underflow(struct intel_context *ce, s32 dt)
>  {
>  #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
> @@ -4601,6 +4602,7 @@ static void init_common_reg_state(u32 * const regs,
>       regs[CTX_CONTEXT_CONTROL] = ctl;
>  
>       regs[CTX_RING_CTL] = RING_CTL_SIZE(ring->size) | RING_VALID;
> +     regs[CTX_TIMESTAMP] = 0;
>  }
>  
>  static void init_wa_bb_reg_state(u32 * const regs,
> -- 
> 2.20.1
>
> _______________________________________________
> Intel-gfx mailing list
> [email protected]
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
_______________________________________________
Intel-gfx mailing list
[email protected]
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

Reply via email to