We need mousevsc_pm_notify() to make sure the pm_wakeup_hard_event() call
does not prevent the system from entering hibernation: the hibernation
is a relatively long process, which can be aborted by the call
pm_wakeup_hard_event(), which is invoked upon mouse events.

Signed-off-by: Dexuan Cui <de...@microsoft.com>
---

This patch is basically a pure Hyper-V specific change and it has a
build dependency on the commit 271b2224d42f ("Drivers: hv: vmbus: Implement
suspend/resume for VSC drivers for hibernation"), which is on Sasha Levin's
Hyper-V tree's hyperv-next branch:
https://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git/log/?h=hyperv-next

I request this patch should go through Sasha's tree rather than the
input subsystem's tree.

Hi Jiri, Benjamin, can you please Ack?

 drivers/hid/hid-hyperv.c | 71 ++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 69 insertions(+), 2 deletions(-)

diff --git a/drivers/hid/hid-hyperv.c b/drivers/hid/hid-hyperv.c
index cc5b09b8..e798740 100644
--- a/drivers/hid/hid-hyperv.c
+++ b/drivers/hid/hid-hyperv.c
@@ -12,6 +12,7 @@
 #include <linux/hid.h>
 #include <linux/hiddev.h>
 #include <linux/hyperv.h>
+#include <linux/suspend.h>
 
 
 struct hv_input_dev_info {
@@ -150,6 +151,9 @@ struct mousevsc_dev {
        struct hv_input_dev_info hid_dev_info;
        struct hid_device       *hid_device;
        u8                      input_buf[HID_MAX_BUFFER_SIZE];
+
+       struct notifier_block   pm_nb;
+       bool                    hibernation_in_progress;
 };
 
 
@@ -192,6 +196,9 @@ static void mousevsc_on_receive_device_info(struct 
mousevsc_dev *input_device,
        if (desc->bLength == 0)
                goto cleanup;
 
+       /* The pointer is not NULL when we resume from hibernation */
+       if (input_device->hid_desc != NULL)
+               kfree(input_device->hid_desc);
        input_device->hid_desc = kmemdup(desc, desc->bLength, GFP_ATOMIC);
 
        if (!input_device->hid_desc)
@@ -203,6 +210,9 @@ static void mousevsc_on_receive_device_info(struct 
mousevsc_dev *input_device,
                goto cleanup;
        }
 
+       /* The pointer is not NULL when we resume from hibernation */
+       if (input_device->report_desc != NULL)
+               kfree(input_device->report_desc);
        input_device->report_desc = kzalloc(input_device->report_desc_size,
                                          GFP_ATOMIC);
 
@@ -243,7 +253,7 @@ static void mousevsc_on_receive_device_info(struct 
mousevsc_dev *input_device,
 }
 
 static void mousevsc_on_receive(struct hv_device *device,
-                               struct vmpacket_descriptor *packet)
+                               const struct vmpacket_descriptor *packet)
 {
        struct pipe_prt_msg *pipe_msg;
        struct synthhid_msg *hid_msg;
@@ -301,7 +311,8 @@ static void mousevsc_on_receive(struct hv_device *device,
                hid_input_report(input_dev->hid_device, HID_INPUT_REPORT,
                                 input_dev->input_buf, len, 1);
 
-               pm_wakeup_hard_event(&input_dev->device->device);
+               if (!input_dev->hibernation_in_progress)
+                       pm_wakeup_hard_event(&input_dev->device->device);
 
                break;
        default:
@@ -378,6 +389,8 @@ static int mousevsc_connect_to_vsp(struct hv_device *device)
        struct mousevsc_prt_msg *request;
        struct mousevsc_prt_msg *response;
 
+       reinit_completion(&input_dev->wait_event);
+
        request = &input_dev->protocol_req;
        memset(request, 0, sizeof(struct mousevsc_prt_msg));
 
@@ -475,6 +488,29 @@ static int mousevsc_hid_raw_request(struct hid_device *hid,
 
 static struct hid_driver mousevsc_hid_driver;
 
+static int mousevsc_pm_notify(struct notifier_block *nb,
+                             unsigned long val, void *ign)
+{
+       struct mousevsc_dev *input_dev;
+
+       input_dev = container_of(nb, struct mousevsc_dev, pm_nb);
+
+       switch (val) {
+       case PM_HIBERNATION_PREPARE:
+       case PM_RESTORE_PREPARE:
+               input_dev->hibernation_in_progress = true;
+               return NOTIFY_OK;
+
+       case PM_POST_HIBERNATION:
+       case PM_POST_RESTORE:
+               input_dev->hibernation_in_progress = false;
+               return NOTIFY_OK;
+
+       default:
+               return NOTIFY_DONE;
+       }
+}
+
 static int mousevsc_probe(struct hv_device *device,
                        const struct hv_vmbus_device_id *dev_id)
 {
@@ -549,6 +585,9 @@ static int mousevsc_probe(struct hv_device *device,
        input_dev->connected = true;
        input_dev->init_complete = true;
 
+       input_dev->pm_nb.notifier_call = mousevsc_pm_notify;
+       register_pm_notifier(&input_dev->pm_nb);
+
        return ret;
 
 probe_err2:
@@ -568,6 +607,8 @@ static int mousevsc_remove(struct hv_device *dev)
 {
        struct mousevsc_dev *input_dev = hv_get_drvdata(dev);
 
+       unregister_pm_notifier(&input_dev->pm_nb);
+
        device_init_wakeup(&dev->device, false);
        vmbus_close(dev->channel);
        hid_hw_stop(input_dev->hid_device);
@@ -577,6 +618,30 @@ static int mousevsc_remove(struct hv_device *dev)
        return 0;
 }
 
+static int mousevsc_suspend(struct hv_device *dev)
+{
+       vmbus_close(dev->channel);
+
+       return 0;
+}
+
+static int mousevsc_resume(struct hv_device *dev)
+{
+       int ret;
+
+       ret = vmbus_open(dev->channel,
+                        INPUTVSC_SEND_RING_BUFFER_SIZE,
+                        INPUTVSC_RECV_RING_BUFFER_SIZE,
+                        NULL, 0,
+                        mousevsc_on_channel_callback,
+                        dev);
+       if (ret)
+               return ret;
+
+       ret = mousevsc_connect_to_vsp(dev);
+       return ret;
+}
+
 static const struct hv_vmbus_device_id id_table[] = {
        /* Mouse guid */
        { HV_MOUSE_GUID, },
@@ -590,6 +655,8 @@ static int mousevsc_remove(struct hv_device *dev)
        .id_table = id_table,
        .probe = mousevsc_probe,
        .remove = mousevsc_remove,
+       .suspend = mousevsc_suspend,
+       .resume = mousevsc_resume,
        .driver = {
                .probe_type = PROBE_PREFER_ASYNCHRONOUS,
        },
-- 
1.8.3.1

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