From: 黄涛 <huangtao@rock-chips.com>
Date: Fri, 24 Aug 2012 09:19:18 +0000 (+0800)
Subject: rga: fix deadlock issue between rga_power_on and rga_power_off_work
X-Git-Tag: firefly_0821_release~8842
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=b618612b8852284f4c5b8a8be1c0c9afbf63c3b6;p=firefly-linux-kernel-4.4.55.git

rga: fix deadlock issue between rga_power_on and rga_power_off_work

Fix this deadlock by call mutex_trylock on rga_power_off_work:

SurfaceFlinger  D c086ec20     0   247      1 0x00000001
[<c086ec20>] (__schedule+0x6d0/0x79c) from [<c086f110>] (schedule_timeout+0x1c/0x208)
[<c086f110>] (schedule_timeout+0x1c/0x208) from [<c086e36c>] (wait_for_common+0xdc/0x178)
[<c086e36c>] (wait_for_common+0xdc/0x178) from [<c04773b8>] (wait_on_work+0xf0/0x158)
[<c04773b8>] (wait_on_work+0xf0/0x158) from [<c0477d30>] (__cancel_work_timer+0xb8/0x104)
[<c0477d30>] (__cancel_work_timer+0xb8/0x104) from [<c05ca548>] (rga_try_set_reg+0x38/0x270)
[<c05ca548>] (rga_try_set_reg+0x38/0x270) from [<c05cafc4>] (rga_blit+0x3b4/0x3fc)
[<c05cafc4>] (rga_blit+0x3b4/0x3fc) from [<c05cb29c>] (rga_ioctl+0x154/0x374)
[<c05cb29c>] (rga_ioctl+0x154/0x374) from [<c04e3480>] (do_vfs_ioctl+0x500/0x57c)
[<c04e3480>] (do_vfs_ioctl+0x500/0x57c) from [<c04e3530>] (sys_ioctl+0x34/0x54)
[<c04e3530>] (sys_ioctl+0x34/0x54) from [<c0435c80>] (ret_fast_syscall+0x0/0x30)
kworker/1:1     D c086ec20     0  7718      2 0x00000000
[<c086ec20>] (__schedule+0x6d0/0x79c) from [<c086f784>] (__mutex_lock_slowpath+0x158/0x1d8)
[<c086f784>] (__mutex_lock_slowpath+0x158/0x1d8) from [<c086f824>] (mutex_lock+0x20/0x38)
[<c086f824>] (mutex_lock+0x20/0x38) from [<c05ca920>] (rga_power_off_work+0x10/0x24)
[<c05ca920>] (rga_power_off_work+0x10/0x24) from [<c0475d74>] (process_one_work+0x250/0x3ac)
[<c0475d74>] (process_one_work+0x250/0x3ac) from [<c04762b4>] (worker_thread+0x228/0x3e8)
[<c04762b4>] (worker_thread+0x228/0x3e8) from [<c047bc18>] (kthread+0x80/0x88)
[<c047bc18>] (kthread+0x80/0x88) from [<c0436678>] (kernel_thread_exit+0x0/0x8)

Also do not call cancel_delayed_work_sync every time.
---

diff --git a/drivers/video/rockchip/rga/rga_drv.c b/drivers/video/rockchip/rga/rga_drv.c
index 6bf2399a59b8..555647126dff 100755
--- a/drivers/video/rockchip/rga/rga_drv.c
+++ b/drivers/video/rockchip/rga/rga_drv.c
@@ -210,11 +210,22 @@ static void rga_dump(void)
 	}
 }
 
+static inline void rga_queue_power_off_work(void)
+{
+	queue_delayed_work(system_nrt_wq, &drvdata->power_off_work, RGA_POWER_OFF_DELAY);
+}
+
 /* Caller must hold rga_service.lock */
 static void rga_power_on(void)
 {
-	cancel_delayed_work_sync(&drvdata->power_off_work);
-	queue_delayed_work(system_nrt_wq, &drvdata->power_off_work, RGA_POWER_OFF_DELAY);
+	static ktime_t last;
+	ktime_t now = ktime_get();
+
+	if (ktime_to_ns(ktime_sub(now, last)) > NSEC_PER_SEC) {
+		cancel_delayed_work_sync(&drvdata->power_off_work);
+		rga_queue_power_off_work();
+		last = now;
+	}
 	if (rga_service.enable)
 		return;
 
@@ -251,9 +262,13 @@ static void rga_power_off(void)
 
 static void rga_power_off_work(struct work_struct *work)
 {
-	mutex_lock(&rga_service.lock);
-	rga_power_off();
-	mutex_unlock(&rga_service.lock);
+	if (mutex_trylock(&rga_service.lock)) {
+		rga_power_off();
+		mutex_unlock(&rga_service.lock);
+	} else {
+		/* Come back later if the device is busy... */
+		rga_queue_power_off_work();
+	}
 }
 
 static int rga_flush(rga_session *session, unsigned long arg)