Commit 754e707e authored by Michal Wajdeczko's avatar Michal Wajdeczko Committed by John Harrison
Browse files

drm/print: Introduce drm_line_printer 



This drm printer wrapper can be used to increase the robustness of
the captured output generated by any other drm_printer to make sure
we didn't lost any intermediate lines of the output by adding line
numbers to each output line. Helpful for capturing some crash data.

v2: Extended short int counters to full int (JohnH)

Signed-off-by: default avatarMichal Wajdeczko <michal.wajdeczko@intel.com>
Signed-off-by: default avatarJohn Harrison <John.C.Harrison@Intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: default avatarJani Nikula <jani.nikula@intel.com>
Acked-by: default avatarMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241003004611.2323493-8-John.C.Harrison@Intel.com
parent d8ce1a97

drivers/gpu/drm/drm_print.c

+14 −0
Original line number Diff line number Diff line
@@ -235,6 +235,20 @@ void __drm_printfn_err(struct drm_printer *p, struct va_format *vaf) 
}

EXPORT_SYMBOL(__drm_printfn_err);



void __drm_printfn_line(struct drm_printer *p, struct va_format *vaf)

{

	unsigned int counter = ++p->line.counter;

	const char *prefix = p->prefix ?: "";

	const char *pad = p->prefix ? " " : "";



	if (p->line.series)

		drm_printf(p->arg, "%s%s%u.%u: %pV",

			   prefix, pad, p->line.series, counter, vaf);

	else

		drm_printf(p->arg, "%s%s%u: %pV", prefix, pad, counter, vaf);

}

EXPORT_SYMBOL(__drm_printfn_line);



/**

 * drm_puts - print a const string to a &drm_printer stream

 * @p: the &drm printer

include/drm/drm_print.h

+64 −0
Original line number Diff line number Diff line
@@ -177,6 +177,10 @@ struct drm_printer { 
	void *arg;

	const void *origin;

	const char *prefix;

	struct {

		unsigned int series;

		unsigned int counter;

	} line;

	enum drm_debug_category category;

};
@@ -187,6 +191,7 @@ 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_dbg(struct drm_printer *p, struct va_format *vaf);

void __drm_printfn_err(struct drm_printer *p, struct va_format *vaf);

void __drm_printfn_line(struct drm_printer *p, struct va_format *vaf);



__printf(2, 3)

void drm_printf(struct drm_printer *p, const char *f, ...);
@@ -411,6 +416,65 @@ static inline struct drm_printer drm_err_printer(struct drm_device *drm, 
	return p;

}



/**

 * drm_line_printer - construct a &drm_printer that prefixes outputs with line numbers

 * @p: the &struct drm_printer which actually generates the output

 * @prefix: optional output prefix, or NULL for no prefix

 * @series: optional unique series identifier, or 0 to omit identifier in the output

 *

 * This printer can be used to increase the robustness of the captured output

 * to make sure we didn't lost any intermediate lines of the output. Helpful

 * while capturing some crash data.

 *

 * Example 1::

 *

 *	void crash_dump(struct drm_device *drm)

 *	{

 *		static unsigned int id;

 *		struct drm_printer p = drm_err_printer(drm, "crash");

 *		struct drm_printer lp = drm_line_printer(&p, "dump", ++id);

 *

 *		drm_printf(&lp, "foo");

 *		drm_printf(&lp, "bar");

 *	}

 *

 * Above code will print into the dmesg something like::

 *

 *	[ ] 0000:00:00.0: [drm] *ERROR* crash dump 1.1: foo

 *	[ ] 0000:00:00.0: [drm] *ERROR* crash dump 1.2: bar

 *

 * Example 2::

 *

 *	void line_dump(struct device *dev)

 *	{

 *		struct drm_printer p = drm_info_printer(dev);

 *		struct drm_printer lp = drm_line_printer(&p, NULL, 0);

 *

 *		drm_printf(&lp, "foo");

 *		drm_printf(&lp, "bar");

 *	}

 *

 * Above code will print::

 *

 *	[ ] 0000:00:00.0: [drm] 1: foo

 *	[ ] 0000:00:00.0: [drm] 2: bar

 *

 * RETURNS:

 * The &drm_printer object

 */

static inline struct drm_printer drm_line_printer(struct drm_printer *p,

						  const char *prefix,

						  unsigned int series)

{

	struct drm_printer lp = {

		.printfn = __drm_printfn_line,

		.arg = p,

		.prefix = prefix,

		.line = { .series = series, },

	};

	return lp;

}



/*

 * struct device based logging

 *