[PATCH v2 1/7] vt: Add con_unblank callback to struct consw

[Thomas Zimmermann]

Add struct consw.con_unblank as inverse operation to con_black.

If implemented invoke con_blank to turn the console from blanked to
unblanked. Also update the semantics of con_blank in this case: The
blank parameter of con_blank receives a VESA blank mode from enum
vesa_blank_mode instead of the hybrid unblank/blank values it has
used so far.

With con_unblank not implemented, invoke con_blank for blanking and
unblanking as before.

The old semantics of con_blank will be removed when all consoles
implement con_unblank.

Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
---
 drivers/tty/vt/vt.c     | 30 +++++++++++++++++++++++-------
 include/linux/console.h |  9 ++++++---
 2 files changed, 29 insertions(+), 10 deletions(-)

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 57edf37495a8..04e28166b78d 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -4671,7 +4671,10 @@ void do_blank_screen(int entering_gfx)
 	if (console_blanked) {
 		if (blank_state == blank_vesa_wait) {
 			blank_state = blank_off;
-			vc->vc_sw->con_blank(vc, vesa_blank_mode + 1, 0);
+			if (vc->vc_sw->con_unblank)
+				vc->vc_sw->con_blank(vc, vesa_blank_mode, 0);
+			else
+				vc->vc_sw->con_blank(vc, vesa_blank_mode + 1, 0);
 		}
 		return;
 	}
@@ -4680,7 +4683,10 @@ void do_blank_screen(int entering_gfx)
 	if (entering_gfx) {
 		hide_cursor(vc);
 		save_screen(vc);
-		vc->vc_sw->con_blank(vc, VESA_VSYNC_SUSPEND, 1);
+		if (vc->vc_sw->con_unblank)
+			vc->vc_sw->con_blank(vc, VESA_NO_BLANKING, 1);
+		else
+			vc->vc_sw->con_blank(vc, VESA_VSYNC_SUSPEND, 1);
 		console_blanked = fg_console + 1;
 		blank_state = blank_off;
 		set_origin(vc);
@@ -4701,8 +4707,12 @@ void do_blank_screen(int entering_gfx)
 
 	save_screen(vc);
 	/* In case we need to reset origin, blanking hook returns 1 */
-	i = vc->vc_sw->con_blank(vc, vesa_off_interval ? VESA_VSYNC_SUSPEND :
-				 (vesa_blank_mode + 1), 0);
+	if (vc->vc_sw->con_unblank)
+		i = vc->vc_sw->con_blank(vc, vesa_off_interval ? VESA_NO_BLANKING :
+					 vesa_blank_mode, 0);
+	else
+		i = vc->vc_sw->con_blank(vc, vesa_off_interval ? VESA_VSYNC_SUSPEND :
+					 (vesa_blank_mode + 1), 0);
 	console_blanked = fg_console + 1;
 	if (i)
 		set_origin(vc);
@@ -4753,9 +4763,15 @@ void do_unblank_screen(int leaving_gfx)
 	}
 
 	console_blanked = 0;
-	if (vc->vc_sw->con_blank(vc, VESA_NO_BLANKING, leaving_gfx))
-		/* Low-level driver cannot restore -> do it ourselves */
-		update_screen(vc);
+	if (vc->vc_sw->con_unblank) {
+		if (vc->vc_sw->con_unblank(vc))
+			/* Low-level driver cannot restore -> do it ourselves */
+			update_screen(vc);
+	} else {
+		if (vc->vc_sw->con_blank(vc, VESA_NO_BLANKING, leaving_gfx))
+			/* Low-level driver cannot restore -> do it ourselves */
+			update_screen(vc);
+	}
 	if (console_blank_hook)
 		console_blank_hook(0);
 	set_palette(vc);
diff --git a/include/linux/console.h b/include/linux/console.h
index 502d1abe3f50..aadcb6053cb0 100644
--- a/include/linux/console.h
+++ b/include/linux/console.h
@@ -55,9 +55,11 @@ enum vc_intensity;
  *		Invoked by csi_M and printing to the console.
  * @con_switch: notifier about the console switch; it is supposed to return
  *		true if a redraw is needed.
- * @con_blank:  blank/unblank the console. The target mode is passed in @blank.
- *		@mode_switch is set if changing from/to text/graphics. The hook
- *		is supposed to return true if a redraw is needed.
+ * @con_blank:  blank the console. The preferred VESA blank mode is passed in
+ *		@blank. @mode_switch is set if changing from/to text/graphics.
+ *		The hook is supposed to return true if a redraw is needed.
+ * @con_unblank:  unblank the console. The hook is supposed to return true if
+ *		a redraw is needed.
  * @con_font_set: set console @vc font to @font with height @vpitch. @flags can
  *		be %KD_FONT_FLAG_DONT_RECALC. (optional)
  * @con_font_get: fetch the current font on @vc of height @vpitch into @font.
@@ -99,6 +101,7 @@ struct consw {
 	bool	(*con_switch)(struct vc_data *vc);
 	bool	(*con_blank)(struct vc_data *vc, enum vesa_blank_mode blank,
 			     bool mode_switch);
+	bool	(*con_unblank)(struct vc_data *vc);
 	int	(*con_font_set)(struct vc_data *vc,
 				const struct console_font *font,
 				unsigned int vpitch, unsigned int flags);
-- 
2.55.0