Disable Suspend-to-Idle in Hyper-V and Fix Hibernation Interruptions

It has been reported that Hyper-V VM users can unintentionally abort hibernation by mouse or keyboard movements. To address this issue, we have decided to remove the wakeup events for the Hyper-V keyboard and mouse driver. However, this change introduces another problem:
Suspend-to-Idle brings the system down with no method to wake it back up.

Given that there are no real users of Suspend-to-Idle in Hyper-V, we have decided to disable this feature for VMBus. This results in:

$echo freeze > /sys/power/state

The keyboard and mouse were previously registered as wakeup sources to interrupt the freeze operation in a VM. Since the freeze operation itself is no longer supported, we are disabling them as wakeup events.

This patchset ensures that the system remains stable and prevents unintended interruptions during hibernation.

Erni Sri Satya Vennela (3):
Drivers: hv: vmbus: Disable Suspend-to-Idle for VMBus Revert "Input: hyperv-keyboard - register as a wakeup source" Revert "HID: hyperv: register as a wakeup source"

 drivers/hid/hid-hyperv.c              |  6 ------
 drivers/hv/vmbus_drv.c                | 16 +++++++++++++++-
 drivers/input/serio/hyperv-keyboard.c | 12 ------------
 3 files changed, 15 insertions(+), 19 deletions(-)

2.34.1

This change is specific to Hyper-V based VMs.
If the Virtual Machine Connection window is focused, a Hyper-V VM user can unintentionally touch the keyboard/mouse when the VM is hibernating or resuming, and consequently the hibernation or resume operation can be aborted unexpectedly. Fix the issue by no longer registering the keyboard/mouse as wakeup devices (see the other two patches for the changes to drivers/input/serio/hyperv-keyboard.c and drivers/hid/hid-hyperv.c).

The keyboard/mouse were registered as wakeup devices because the VM needs to be woken up from the Suspend-to-Idle state after a user runs "echo freeze > /sys/power/state". It seems like the Suspend-to-Idle feature has no real users in practice, so let's no longer support that by returning -EOPNOTSUPP if a user tries to use that.

$echo freeze > /sys/power/state

---
Changes in v2:
* Add "#define vmbus_freeze NULL" when CONFIG_PM_SLEEP is not enabled.
* Change commit message to clarify that this change is specifc to Hyper-V based VMs.
Changes in v3:
* Add 'Cc: [email protected]' in sign-off area.

---
 drivers/hv/vmbus_drv.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

index 965d2a4efb7e..8f445c849512 100644
@@ -900,6 +900,19 @@ static void vmbus_shutdown(struct device *child_device)
 }
 
 #ifdef CONFIG_PM_SLEEP
+/*
+ * vmbus_freeze - Suspend-to-Idle
+ */
+static int vmbus_freeze(struct device *child_device)
+{
+/*
+ * Do not support Suspend-to-Idle ("echo freeze > /sys/power/state") as
+ * that would require registering the Hyper-V synthetic mouse/keyboard
+ * devices as wakeup devices, which can abort hibernation/resume unexpectedly.
+ */
+	return -EOPNOTSUPP;
+}
+
 /*
  * vmbus_suspend - Suspend a vmbus device
  */

@@ -938,6 +951,7 @@ static int vmbus_resume(struct device *child_device)
 	return drv->resume(dev);
 }
 #else
+#define vmbus_freeze NULL
 #define vmbus_suspend NULL
 #define vmbus_resume NULL
 #endif /* CONFIG_PM_SLEEP */

@@ -969,7 +983,7 @@ static void vmbus_device_release(struct device *device)
  */
 
 static const struct dev_pm_ops vmbus_pm = {
-	.suspend_noirq	= NULL,
+	.suspend_noirq  = vmbus_freeze,
 	.resume_noirq	= NULL,
 	.freeze_noirq	= vmbus_suspend,
 	.thaw_noirq	= vmbus_resume,

2.34.1

This reverts commit 62238f3aadc9bc56da70100e19ec61b9f8d72a5f.

Remove keyboard as wakeup source since Suspend-To-Idle feature is disabled.

---
 drivers/input/serio/hyperv-keyboard.c | 12 ------------
 1 file changed, 12 deletions(-)

index 31d9dacd2fd1..b42c546636bf 100644
@@ -162,15 +162,6 @@ static void hv_kbd_on_receive(struct hv_device *hv_dev,
 			serio_interrupt(kbd_dev->hv_serio, scan_code, 0);
 		}
 		spin_unlock_irqrestore(&kbd_dev->lock, flags);
-
-		/*
-		 * Only trigger a wakeup on key down, otherwise
-		 * "echo freeze > /sys/power/state" can't really enter the
-		 * state because the Enter-UP can trigger a wakeup at once.
-		 */
-		if (!(info & IS_BREAK))
-			pm_wakeup_hard_event(&hv_dev->device);
-
 		break;
 
 	default:

@@ -356,9 +347,6 @@ static int hv_kbd_probe(struct hv_device *hv_dev,
 		goto err_close_vmbus;
 
 	serio_register_port(kbd_dev->hv_serio);
-
-	device_init_wakeup(&hv_dev->device, true);
-
 	return 0;
 
 err_close_vmbus:

2.34.1

This reverts commit f1210455e78a610c7b316389b31c162c371d888c.

Remove mouse as wakeup source since Suspend-To-Idle feature is disabled.

---
 drivers/hid/hid-hyperv.c | 6 ------
 1 file changed, 6 deletions(-)

index f33485d83d24..b6d0f7db4c93 100644
@@ -293,9 +293,6 @@ static void mousevsc_on_receive(struct hv_device *device,
 		memcpy(input_dev->input_buf, input_report->buffer, len);
 		hid_input_report(input_dev->hid_device, HID_INPUT_REPORT,
 				 input_dev->input_buf, len, 1);
-
-		pm_wakeup_hard_event(&input_dev->device->device);
-
 		break;
 	default:
 		pr_err("unsupported hid msg type - type %d len %d\n",

@@ -502,8 +499,6 @@ static int mousevsc_probe(struct hv_device *device,
 		goto probe_err2;
 	}
 
-	device_init_wakeup(&device->device, true);
-
 	input_dev->connected = true;
 	input_dev->init_complete = true;
 

@@ -526,7 +521,6 @@ static void mousevsc_remove(struct hv_device *dev)
 {
 	struct mousevsc_dev *input_dev = hv_get_drvdata(dev);
 
-	device_init_wakeup(&dev->device, false);
 	vmbus_close(dev->channel);
 	hid_hw_stop(input_dev->hid_device);
 	hid_destroy_device(input_dev->hid_device);

2.34.1