Make sure the unicode screen buffer matches the video screen content.
This is provided for debugging convenience and disabled by default.
Signed-off-by: Nicolas Pitre <n...@linaro.org>
---
drivers/tty/vt/vt.c | 39 +++++++++++++++++++++++++++++++++++++++
1 file changed, 39 insertions(+)
diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 2d14bb195d..81129671c9 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -321,6 +321,8 @@ void schedule_console_callback(void)
* Code to manage unicode-based screen buffers
*/
+#define VC_UNI_SCREEN_DEBUG 0
+
#ifdef NO_VC_UNI_SCREEN
/* this disables and optimizes related code away at compile time */
#define get_vc_uniscr(vc) NULL
@@ -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_notice("%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);
--
2.17.1
