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Commit 0224080f authored by Nicolas Pitre's avatar Nicolas Pitre Committed by Greg Kroah-Hartman
Browse files

vt: coherence validation code for the unicode screen buffer 



Make sure the unicode screen buffer matches the video screen content.
This is provided for debugging convenience and disabled by default.

Signed-off-by: default avatarNicolas Pitre <nico@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 9bfdc261

drivers/tty/vt/vt.c

+39 −0
Original line number Diff line number Diff line
@@ -328,6 +328,8 @@ void schedule_console_callback(void) 
#define get_vc_uniscr(vc) vc->vc_uni_screen

#endif



#define VC_UNI_SCREEN_DEBUG 0



typedef uint32_t char32_t;



/*
@@ -569,6 +571,42 @@ void vc_uniscr_copy_line(struct vc_data *vc, void *dest, int viewed, 
	}

}



/* this is for validation and debugging only */

static void vc_uniscr_debug_check(struct vc_data *vc)

{

	struct uni_screen *uniscr = get_vc_uniscr(vc);

	unsigned short *p;

	int x, y, mask;



	if (!VC_UNI_SCREEN_DEBUG || !uniscr)

		return;



	WARN_CONSOLE_UNLOCKED();



	/*

	 * Make sure our unicode screen translates into the same glyphs

	 * as the actual screen. This is brutal indeed.

	 */

	p = (unsigned short *)vc->vc_origin;

	mask = vc->vc_hi_font_mask | 0xff;

	for (y = 0; y < vc->vc_rows; y++) {

		char32_t *line = uniscr->lines[y];

		for (x = 0; x < vc->vc_cols; x++) {

			u16 glyph = scr_readw(p++) & mask;

			char32_t uc = line[x];

			int tc = conv_uni_to_pc(vc, uc);

			if (tc == -4)

				tc = conv_uni_to_pc(vc, 0xfffd);

			if (tc == -4)

				tc = conv_uni_to_pc(vc, '?');

			if (tc != glyph)

				pr_err_ratelimited(

					"%s: mismatch at %d,%d: glyph=%#x tc=%#x\n",

					__func__, x, y, glyph, tc);

		}

	}

}





static void con_scroll(struct vc_data *vc, unsigned int t, unsigned int b,

		enum con_scroll dir, unsigned int nr)
@@ -2717,6 +2755,7 @@ static int do_con_write(struct tty_struct *tty, const unsigned char *buf, int co 
		do_con_trol(tty, vc, orig);

	}

	con_flush(vc, draw_from, draw_to, &draw_x);

	vc_uniscr_debug_check(vc);

	console_conditional_schedule();

	console_unlock();

	notify_update(vc);