[PATCH v4 3/5] vgacon: Use vt_cursor_{start,end}()

[Thomas Zimmermann <tzimmermann@suse.de>]

Replace vgacon's custom cursor metrics with the shared helpers
vc_cursor_start() and vc_font_cursor_end(). Note that the _end()
function returns the index of the scanline below the cursor, while
VGA hardware expects the cursor's final scanline. Hence vgacon
subtracts 1 from the end value.

The cursor shapes remain mostly unchanged, except that non-underline
cursors now also use the glyph's top-most and bottom-most scanline.
This follows the style used by fbcon.

v4:
- disable if CUR_DEF maps to CUR_NONE
v2:
- restore use of vc_cell_height (Sashiko)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Helge Deller <deller@gmx.de>
---
 drivers/video/console/vgacon.c | 33 +++++----------------------------
 1 file changed, 5 insertions(+), 28 deletions(-)

diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
index 536e7fe4d142..2dcb1e38bd6b 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c
@@ -506,6 +506,7 @@ static void vgacon_set_cursor_size(int from, int to)
 static void vgacon_cursor(struct vc_data *c, bool enable)
 {
 	unsigned int c_height;
+	unsigned int c_size;
 
 	if (c->vc_mode != KD_TEXT)
 		return;
@@ -513,10 +514,11 @@ static void vgacon_cursor(struct vc_data *c, bool enable)
 	vgacon_restore_screen(c);
 
 	c_height = c->vc_cell_height;
+	c_size = vc_cursor_valid_size(CUR_SIZE(c->vc_cursor_type));
 
 	write_vga(14, (c->vc_pos - vga_vram_base) / 2);
 
-	if (!enable) {
+	if (!enable || c_size == CUR_NONE) {
 	        if (vga_video_type >= VIDEO_TYPE_VGAC)
 			vgacon_set_cursor_size(31, 30);
 		else
@@ -524,33 +526,8 @@ static void vgacon_cursor(struct vc_data *c, bool enable)
 		return;
 	}
 
-	switch (CUR_SIZE(c->vc_cursor_type)) {
-	case CUR_UNDERLINE:
-		vgacon_set_cursor_size(c_height - (c_height < 10 ? 2 : 3),
-				       c_height - (c_height < 10 ? 1 : 2));
-		break;
-	case CUR_TWO_THIRDS:
-		vgacon_set_cursor_size(c_height / 3,
-				       c_height - (c_height < 10 ? 1 : 2));
-		break;
-	case CUR_LOWER_THIRD:
-		vgacon_set_cursor_size(c_height * 2 / 3,
-				       c_height - (c_height < 10 ? 1 : 2));
-		break;
-	case CUR_LOWER_HALF:
-		vgacon_set_cursor_size(c_height / 2,
-				       c_height - (c_height < 10 ? 1 : 2));
-		break;
-	case CUR_NONE:
-		if (vga_video_type >= VIDEO_TYPE_VGAC)
-			vgacon_set_cursor_size(31, 30);
-		else
-			vgacon_set_cursor_size(31, 31);
-		break;
-	default:
-		vgacon_set_cursor_size(1, c_height);
-		break;
-	}
+	vgacon_set_cursor_size(vc_cursor_start(c_height, c_size),
+			       vc_cursor_end(c_height, c_size) - 1);
 }
 
 static void vgacon_doresize(struct vc_data *c,
-- 
2.55.0