[PATCH 1/2] drm/printer: add debug printer

[Chris Wilson]

On Wed, Dec 28, 2016 at 05:42:09PM +0100, Daniel Vetter wrote:
> Useful for dumping lots of data into dmesg, e.g. drm_mm.
> 
> Cc: Rob Clark <robdclark at gmail.com>
> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
> ---
>  drivers/gpu/drm/drm_print.c |  6 ++++++
>  include/drm/drm_print.h     | 20 ++++++++++++++++++--
>  2 files changed, 24 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
> index ad3caaa1f48b..a8300cd2d3b3 100644
> --- a/drivers/gpu/drm/drm_print.c
> +++ b/drivers/gpu/drm/drm_print.c
> @@ -40,6 +40,12 @@ void __drm_printfn_info(struct drm_printer *p, struct va_format *vaf)
>  }
>  EXPORT_SYMBOL(__drm_printfn_info);
>  
> +void __drm_printfn_debug(struct drm_printer *p, struct va_format *vaf)
> +{
> +	pr_debug("%s %pV", p->prefix, vaf);
> +}
> +EXPORT_SYMBOL(__drm_printfn_info);

Ahem.

> +
>  /**
>   * drm_printf - print to a &drm_printer stream
>   * @p: the &drm_printer
> diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
> index 1adf84aea622..e9d0ba20089c 100644
> --- a/include/drm/drm_print.h
> +++ b/include/drm/drm_print.h
> @@ -60,19 +60,20 @@
>  
>  /**
>   * struct drm_printer - drm output "stream"
> - * @printfn: actual output fxn
> - * @arg: output fxn specific data
>   *
>   * Do not use struct members directly.  Use drm_printer_seq_file(),
>   * drm_printer_info(), etc to initialize.  And drm_printf() for output.
>   */
>  struct drm_printer {
> +	/* private: */
>  	void (*printfn)(struct drm_printer *p, struct va_format *vaf);
>  	void *arg;
> +	const char *prefix;
>  };
>  
>  void __drm_printfn_seq_file(struct drm_printer *p, struct va_format *vaf);
>  void __drm_printfn_info(struct drm_printer *p, struct va_format *vaf);
> +void __drm_printfn_debug(struct drm_printer *p, struct va_format *vaf);
>  
>  void drm_printf(struct drm_printer *p, const char *f, ...);
>  
> @@ -109,4 +110,19 @@ static inline struct drm_printer drm_info_printer(struct device *dev)
>  	return p;
>  }
>  
> +/**
> + * drm_debug_printer - construct a &drm_printer that outputs to pr_debug()
> + * @prefix: debug output prefix
> + *
> + * RETURNS:
> + * The &drm_printer object
> + */
> +static inline struct drm_printer drm_debug_printer(const char *prefix)
> +{
> +	struct drm_printer p = {
> +		.printfn = __drm_printfn_debug,
> +		.prefix = prefix
> +	};
> +	return p;
> +}

\n

>  #endif /* DRM_PRINT_H_ */

I was looking at a single __drm_printfn callback with a
drm_printer.level, but we lose the dynamic debug goodness.

With the EXPORT_SYMBOL fixed,
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre