clapper: glimmer: fix for keyboard occasionally disabled on wake

Fixes bug in which the keyboard remains disabled after resuming.
The problem occurs when the lidangle_keyscan_update() occurs after
the CHIPSET_RESUME hook triggers and before chipset state is
CHIPSET_STATE_ON, and the lid angle is in range to disable the
keyboard.

The fix is to not use a hook at all on chipset resume, and instead
just keep track of the last chipset state locally in
lidangle_keyscan_update(). That way we guarantee that when the
AP is turned on, the next time we check for lidangle keyscanning
state, it will enable the keyboard.

BUG=chrome-os-partner:28480
BRANCH=rambi
TEST=tested on a glimmer:

Added a hook to detect chipset resume in lid_angle.c:
static void enable_keyboard(void)
{
	hook_fired = 1;
}
DECLARE_HOOK(HOOK_CHIPSET_RESUME, enable_keyboard, HOOK_PRIO_DEFAULT);

Then in lidangle_keyscan_update() added:
if (hook_fired && !chipset_in_state(CHIPSET_STATE_ON))
        ccprintf("Hook fired, but chipset state still reads off\n");
hook_fired = 0;

Using this code, I used the lid switch on the servo board to open
and close the lid repeatedly until I saw the printf above.

Without this CL, when the printf is shown, the keyboard remains
disabled in S0. With this CL, the keyboard is enabled in S0.

Change-Id: Iac017a6468d46e0f011ec9d84a8c73b89622d8cc
Signed-off-by: Alec Berg <alecaberg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/198285
Reviewed-by: Randall Spangler <rspangler@chromium.org>

1 files changed, 14 insertions, 11 deletions

diff --git a/common/lid_angle.c b/common/lid_angle.c
index 2bee31d8c9..fa9e71dee6 100644
--- a/common/lid_angle.c
+++ b/common/lid_angle.c
@@ -118,6 +118,7 @@ void lidangle_keyscan_update(float lid_ang)
 {
 	static float lidangle_buffer[KEY_SCAN_LID_ANGLE_BUFFER_SIZE];
 	static int index;
+	static int last_chipset_state_on;
 
 	int i;
 	int keys_accept = 1, keys_ignore = 1;
@@ -131,6 +132,7 @@ void lidangle_keyscan_update(float lid_ang)
 	 * is enabled based on lid angle history.
 	 */
 	if (!chipset_in_state(CHIPSET_STATE_ON)) {
+		last_chipset_state_on = 0;
 		for (i = 0; i < KEY_SCAN_LID_ANGLE_BUFFER_SIZE; i++) {
 			/*
 			 * If any lid angle samples are unreliable, then
@@ -153,17 +155,18 @@ void lidangle_keyscan_update(float lid_ang)
 		/* Enable or disable keyboard scanning as necessary. */
 		if (keys_accept)
 			keyboard_scan_enable(1, KB_SCAN_DISABLE_LID_ANGLE);
-		else if (keys_ignore && !keys_accept)
+		else if (keys_ignore)
 			keyboard_scan_enable(0, KB_SCAN_DISABLE_LID_ANGLE);
+	} else {
+		/*
+		 * Make sure lid angle is not disabling keyboard scanning when
+		 * AP is running. Note, we can't use a hook here for chipset
+		 * resume because the hook triggers before the chipset state
+		 * variable changes, (crosbug.com/p/28529)
+		 */
+		if (!last_chipset_state_on) {
+			keyboard_scan_enable(1, KB_SCAN_DISABLE_LID_ANGLE);
+			last_chipset_state_on = 1;
+		}
 	}
 }
-
-static void enable_keyboard(void)
-{
-	/*
-	 * Make sure lid angle is not disabling keyboard scanning when AP is
-	 * running.
-	 */
-	keyboard_scan_enable(1, KB_SCAN_DISABLE_LID_ANGLE);
-}
-DECLARE_HOOK(HOOK_CHIPSET_RESUME, enable_keyboard, HOOK_PRIO_DEFAULT);