[Intel-xe] [PATCH 6/7] drm/xe/reg_sr: Save errors for kunit integration

[Michał Winiarski]

On Tue, Mar 21, 2023 at 03:05:26PM -0700, Lucas De Marchi wrote:
> When there's an entry that is dropped when xe_reg_sr_add(), there's
> not much we can do other than reporting the error - it's for certain a
> driver issue or conflicting workarounds/tunings. Save the number of
> errors to be used later by kunit to report where it happens.

Why there's not much we can do?
We can propagate the error to the upper layers and fail the probe.
Fail-fast?

The following test still makes sense (and LGTM), since it's still a good
idea to be able to validate everything without having to probe() on
actual platform. I would expect it to check return values rather than
sr->errors though.

-Michał

> 
> Signed-off-by: Lucas De Marchi <lucas.demarchi at intel.com>
> ---
>  drivers/gpu/drm/xe/xe_reg_sr.c       | 8 ++++++++
>  drivers/gpu/drm/xe/xe_reg_sr_types.h | 4 ++++
>  2 files changed, 12 insertions(+)
> 
> diff --git a/drivers/gpu/drm/xe/xe_reg_sr.c b/drivers/gpu/drm/xe/xe_reg_sr.c
> index 9eaf1be27886..83f29aeb9250 100644
> --- a/drivers/gpu/drm/xe/xe_reg_sr.c
> +++ b/drivers/gpu/drm/xe/xe_reg_sr.c
> @@ -84,6 +84,13 @@ static bool compatible_entries(const struct xe_reg_sr_entry *e1,
>  	return true;
>  }
>  
> +static void reg_sr_inc_error(struct xe_reg_sr *sr)
> +{
> +#if IS_ENABLED(CONFIG_DRM_XE_KUNIT_TEST)
> +	sr->errors++;
> +#endif
> +}
> +
>  int xe_reg_sr_add(struct xe_reg_sr *sr, u32 reg,
>  		  const struct xe_reg_sr_entry *e)
>  {
> @@ -121,6 +128,7 @@ int xe_reg_sr_add(struct xe_reg_sr *sr, u32 reg,
>  	DRM_ERROR("Discarding save-restore reg %04lx (clear: %08x, set: %08x, masked: %s): ret=%d\n",
>  		  idx, e->clr_bits, e->set_bits,
>  		  str_yes_no(e->masked_reg), ret);
> +	reg_sr_inc_error(sr);
>  
>  	return ret;
>  }
> diff --git a/drivers/gpu/drm/xe/xe_reg_sr_types.h b/drivers/gpu/drm/xe/xe_reg_sr_types.h
> index 3d2257891005..91469784fd90 100644
> --- a/drivers/gpu/drm/xe/xe_reg_sr_types.h
> +++ b/drivers/gpu/drm/xe/xe_reg_sr_types.h
> @@ -32,6 +32,10 @@ struct xe_reg_sr {
>  	} pool;
>  	struct xarray xa;
>  	const char *name;
> +
> +#if IS_ENABLED(CONFIG_DRM_XE_KUNIT_TEST)
> +	unsigned int errors;
> +#endif
>  };
>  
>  #endif
> -- 
> 2.39.0
>