tty: vt: remove vc_uniscr_debug_check()

VC_UNI_SCREEN_DEBUG is always defined as 0, so this code is never
executed. Drop it along with VC_UNI_SCREEN_DEBUG.
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20230112080136.4929-1-jirislaby@kernel.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/vt/vt.c

@@ -323,8 +323,6 @@ 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;
 
 /*
@@ -580,43 +578,6 @@ void vc_uniscr_copy_line(const struct vc_data *vc, void *dest, bool 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)
 {
@@ -2959,7 +2920,6 @@ static int do_con_write(struct tty_struct *tty, const unsigned char *buf, int co
 			goto rescan_last_byte;
 	}
 	con_flush(vc, &draw);
-	vc_uniscr_debug_check(vc);
 	console_conditional_schedule();
 	notify_update(vc);
 	console_unlock();