[PATCH 03/10] drm/print: add drm_dbg_printer() for drm device specific printer

[Luca Coelho]

On Tue, 2024-01-16 at 15:07 +0200, Jani Nikula wrote:
> We've lacked a device specific debug printer. Add one. Take category
> into account too.
> 
> __builtin_return_address(0) is inaccurate here, so don't use it. If
> necessary, we can later pass __func__ to drm_dbg_printer() by wrapping
> it inside a macro.
> 
> Signed-off-by: Jani Nikula <jani.nikula at intel.com>
> ---
>  drivers/gpu/drm/drm_print.c | 21 +++++++++++++++++++++
>  include/drm/drm_print.h     | 24 ++++++++++++++++++++++++
>  2 files changed, 45 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
> index 91dbcdeaad3f..673b29c732ea 100644
> --- a/drivers/gpu/drm/drm_print.c
> +++ b/drivers/gpu/drm/drm_print.c
> @@ -189,6 +189,27 @@ void __drm_printfn_debug(struct drm_printer *p, struct va_format *vaf)
>  }
>  EXPORT_SYMBOL(__drm_printfn_debug);
>  
> +void __drm_printfn_dbg(struct drm_printer *p, struct va_format *vaf)
> +{
> +	const struct drm_device *drm = p->arg;
> +	const struct device *dev = drm ? drm->dev : NULL;
> +	enum drm_debug_category category = p->category;
> +	const char *prefix = p->prefix ?: "";
> +	const char *prefix_pad = p->prefix ? " " : "";
> +
> +	if (!__drm_debug_enabled(category))
> +		return;
> +
> +	/* Note: __builtin_return_address(0) is useless here. */
> +	if (dev)
> +		dev_printk(KERN_DEBUG, dev, "[" DRM_NAME "]%s%s %pV",
> +			   prefix_pad, prefix, vaf);
> +	else
> +		printk(KERN_DEBUG "[" DRM_NAME "]%s%s %pV",
> +		       prefix_pad, prefix, vaf);
> +}
> +EXPORT_SYMBOL(__drm_printfn_dbg);
> +
>  void __drm_printfn_err(struct drm_printer *p, struct va_format *vaf)
>  {
>  	struct drm_device *drm = p->arg;
> diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
> index b8b4cb9bb878..27e23c06dad4 100644
> --- a/include/drm/drm_print.h
> +++ b/include/drm/drm_print.h
> @@ -176,6 +176,7 @@ struct drm_printer {
>  	void (*puts)(struct drm_printer *p, const char *str);
>  	void *arg;
>  	const char *prefix;
> +	enum drm_debug_category category;
>  };
>  
>  void __drm_printfn_coredump(struct drm_printer *p, struct va_format *vaf);
> @@ -184,6 +185,7 @@ void __drm_printfn_seq_file(struct drm_printer *p, struct va_format *vaf);
>  void __drm_puts_seq_file(struct drm_printer *p, const char *str);
>  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_printfn_dbg(struct drm_printer *p, struct va_format *vaf);

I was wondering why you had both _debug() and _dbg() functions here,
but I see your goal is to remove _debug() at the end (done in the last
patch in the series).


>  void __drm_printfn_err(struct drm_printer *p, struct va_format *vaf);
>  
>  __printf(2, 3)
> @@ -331,6 +333,28 @@ static inline struct drm_printer drm_debug_printer(const char *prefix)
>  	return p;
>  }
>  
> +/**
> + * drm_dbg_printer - construct a &drm_printer for drm device specific output
> + * @drm: the &struct drm_device pointer, or NULL
> + * @category: the debug category to use
> + * @prefix: debug output prefix, or NULL for no prefix
> + *
> + * RETURNS:
> + * The &drm_printer object
> + */
> +static inline struct drm_printer drm_dbg_printer(struct drm_device *drm,
> +						 enum drm_debug_category category,
> +						 const char *prefix)
> +{
> +	struct drm_printer p = {
> +		.printfn = __drm_printfn_dbg,
> +		.arg = drm,
> +		.prefix = prefix,
> +		.category = category,
> +	};
> +	return p;
> +}
> +
>  /**
>   * drm_err_printer - construct a &drm_printer that outputs to drm_err()
>   * @drm: the &struct drm_device pointer

Reviewed-by: Luca Coelho <luciano.coelho at intel.com>

--
Cheers,
Luca.