[RFC 6/6] drm/i915: Allow configuring default request expiry via modparam

[Daniel Vetter]

On Fri, Mar 12, 2021 at 03:46:22PM +0000, Tvrtko Ursulin wrote:
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> 
> Module parameter is added (request_timeout_ms) to allow configuring the
> default request/fence expiry.
> 
> Default value is inherited from CONFIG_DRM_I915_REQUEST_TIMEOUT.
> 
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>

Yeah I think this makes sense for debugging and testing (e.g. in igt we
can crank down the timeout to make stuff fail real fast, could help with
runtime on some tests).

Acked-by: Daniel Vetter <daniel.vetter at ffwll.ch>

Cheers, Daniel

> ---
>  drivers/gpu/drm/i915/gem/i915_gem_context.c | 8 +++++---
>  drivers/gpu/drm/i915/i915_params.c          | 5 +++++
>  drivers/gpu/drm/i915/i915_params.h          | 1 +
>  3 files changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> index 21c0176e27a0..1dae5e2514a9 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> @@ -866,7 +866,7 @@ static void __set_default_fence_expiry(struct i915_gem_context *ctx)
>  		return;
>  
>  	/* Default expiry for user fences. */
> -	ret = __set_watchdog(ctx, CONFIG_DRM_I915_REQUEST_TIMEOUT * 1000);
> +	ret = __set_watchdog(ctx, i915->params.request_timeout_ms * 1000);
>  	if (ret)
>  		drm_notice(&i915->drm,
>  			   "Failed to configure default fence expiry! (%d)",
> @@ -1442,13 +1442,15 @@ __set_watchdog(struct i915_gem_context *ctx, unsigned long timeout_us)
>  static int set_watchdog(struct i915_gem_context *ctx,
>  			struct drm_i915_gem_context_param *args)
>  {
> +	struct drm_i915_private *i915 = ctx->i915;
> +
>  	if (args->size)
>  		return -EINVAL;
>  
>  	/* Disallow disabling or configuring longer watchdog than default. */
> -	if (IS_ACTIVE(CONFIG_DRM_I915_REQUEST_TIMEOUT) &&
> +	if (i915->params.request_timeout_ms &&
>  	    (!args->value ||
> -	     args->value > CONFIG_DRM_I915_REQUEST_TIMEOUT * 1000))
> +	     args->value > i915->params.request_timeout_ms * 1000))
>  		return -EPERM;
>  
>  	return __set_watchdog(ctx, args->value);
> diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
> index 6939634e56ed..0320878d96b0 100644
> --- a/drivers/gpu/drm/i915/i915_params.c
> +++ b/drivers/gpu/drm/i915/i915_params.c
> @@ -197,6 +197,11 @@ i915_param_named_unsafe(fake_lmem_start, ulong, 0400,
>  	"Fake LMEM start offset (default: 0)");
>  #endif
>  
> +#if CONFIG_DRM_I915_REQUEST_TIMEOUT
> +i915_param_named_unsafe(request_timeout_ms, uint, 0600,
> +			"Default request/fence/batch buffer expiration timeout.");
> +#endif
> +
>  static __always_inline void _print_param(struct drm_printer *p,
>  					 const char *name,
>  					 const char *type,
> diff --git a/drivers/gpu/drm/i915/i915_params.h b/drivers/gpu/drm/i915/i915_params.h
> index 48f47e44e848..34ebb0662547 100644
> --- a/drivers/gpu/drm/i915/i915_params.h
> +++ b/drivers/gpu/drm/i915/i915_params.h
> @@ -72,6 +72,7 @@ struct drm_printer;
>  	param(int, enable_dpcd_backlight, -1, 0600) \
>  	param(char *, force_probe, CONFIG_DRM_I915_FORCE_PROBE, 0400) \
>  	param(unsigned long, fake_lmem_start, 0, 0400) \
> +	param(unsigned int, request_timeout_ms, CONFIG_DRM_I915_REQUEST_TIMEOUT, 0600) \
>  	/* leave bools at the end to not create holes */ \
>  	param(bool, enable_hangcheck, true, 0600) \
>  	param(bool, load_detect_test, false, 0600) \
> -- 
> 2.27.0
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch