From afcef8440b18f69ed153ea9574dc68d1f55c8c6c Mon Sep 17 00:00:00 2001
From: tmk <nobody@nowhere>
Date: Tue, 5 Mar 2013 19:18:01 +0900
Subject: [PATCH 1/2] Fix ghost block and remove matrix_has_ghost()

---
 common/keyboard.c | 25 ++++++++++++++++++++++++-
 common/matrix.h   |  2 --
 2 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/common/keyboard.c b/common/keyboard.c
index 432ea893..91f321d9 100644
--- a/common/keyboard.c
+++ b/common/keyboard.c
@@ -34,6 +34,24 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #endif
 
 
+#ifdef MATRIX_HAS_GHOST
+static bool has_ghost_in_row(uint8_t row)
+{
+    matrix_row_t matrix_row = matrix_get_row(row);
+    // No ghost exists when less than 2 keys are down on the row
+    if (((matrix_row - 1) & matrix_row) == 0)
+        return false;
+
+    // Ghost occurs when the row shares column line with other row
+    for (uint8_t i=0; i < MATRIX_ROWS; i++) {
+        if (i != row && (matrix_get_row(i) & matrix_row))
+            return true;
+    }
+    return false;
+}
+#endif
+
+
 void keyboard_init(void)
 {
     // TODO: configuration of sendchar impl
@@ -81,7 +99,12 @@ void keyboard_task(void)
         matrix_change = matrix_row ^ matrix_prev[r];
         if (matrix_change) {
             if (debug_matrix) matrix_print();
-
+#ifdef MATRIX_HAS_GHOST
+            if (has_ghost_in_row(r)) {
+                matrix_prev[r] = matrix_row;
+                continue;
+            }
+#endif
             for (uint8_t c = 0; c < MATRIX_COLS; c++) {
                 if (matrix_change & ((matrix_row_t)1<<c)) {
                     action_exec((keyevent_t){
diff --git a/common/matrix.h b/common/matrix.h
index b3332d5f..48203c71 100644
--- a/common/matrix.h
+++ b/common/matrix.h
@@ -45,8 +45,6 @@ void matrix_init(void);
 uint8_t matrix_scan(void);
 /* whether modified from previous scan. used after matrix_scan. */
 bool matrix_is_modified(void);
-/* whether ghosting occur on matrix. */
-bool matrix_has_ghost(void);
 /* whether a swtich is on */
 bool matrix_is_on(uint8_t row, uint8_t col);
 /* matrix state on row */

From 0e48c565866231fb89707d41b209ef79af5b6bb2 Mon Sep 17 00:00:00 2001
From: tmk <nobody@nowhere>
Date: Tue, 5 Mar 2013 21:20:39 +0900
Subject: [PATCH 2/2] Remove matrix_key_count() from matrix.h

---
 common/matrix.h | 2 --
 1 file changed, 2 deletions(-)

diff --git a/common/matrix.h b/common/matrix.h
index 48203c71..d62acb66 100644
--- a/common/matrix.h
+++ b/common/matrix.h
@@ -49,8 +49,6 @@ bool matrix_is_modified(void);
 bool matrix_is_on(uint8_t row, uint8_t col);
 /* matrix state on row */
 matrix_row_t  matrix_get_row(uint8_t row);
-/* count keys pressed */
-uint8_t matrix_key_count(void);
 /* print matrix for debug */
 void matrix_print(void);