[PATCH v2 6/6] HID: intel-ish-hid: ipc: Separate hibernate callbacks in dev_pm_ops

[Zhang Lixu <lixu.zhang@intel.com>]

The same suspend and resume callbacks are used for both suspend-to-RAM/idle
and hibernation. These callbacks invoke pm_suspend_via_firmware() and
pm_resume_via_firmware(), respectively. In the .freeze() of hibernation,
pm_suspend_via_firmware() returns false, causing the driver to put ISH into
D0i3. However, during the .thaw(), pm_resume_via_firmware() returns true,
leading the driver to treat ISH as resuming from D3 instead of D0i3. The
asymmetric behavior between .freeze() and .thaw() during hibernation can
cause the client connection states on the firmware side and the driver side
to become inconsistent.

To address the inconsistent client connection states issue, separate
hibernate-related callbacks (freeze, thaw) in dev_pm_ops. Since ISH does
not need to save any firmware-related state when entering hibernation, it
is sufficient to call pci_save_state() in .freeze() to prevent the PCI bus
from changing the ISH power state. No actions are required in .thaw().

Signed-off-by: Zhang Lixu <lixu.zhang@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
---
 drivers/hid/intel-ish-hid/ipc/pci-ish.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/intel-ish-hid/ipc/pci-ish.c b/drivers/hid/intel-ish-hid/ipc/pci-ish.c
index e4499c83c62e..1612e8cb23f0 100644
--- a/drivers/hid/intel-ish-hid/ipc/pci-ish.c
+++ b/drivers/hid/intel-ish-hid/ipc/pci-ish.c
@@ -397,7 +397,20 @@ static int __maybe_unused ish_resume(struct device *device)
 	return 0;
 }
 
-static SIMPLE_DEV_PM_OPS(ish_pm_ops, ish_suspend, ish_resume);
+static int __maybe_unused ish_freeze(struct device *device)
+{
+	struct pci_dev *pdev = to_pci_dev(device);
+
+	return pci_save_state(pdev);
+}
+
+static const struct dev_pm_ops __maybe_unused ish_pm_ops = {
+	.suspend = pm_sleep_ptr(ish_suspend),
+	.resume = pm_sleep_ptr(ish_resume),
+	.freeze = pm_sleep_ptr(ish_freeze),
+	.restore = pm_sleep_ptr(ish_resume),
+	.poweroff = pm_sleep_ptr(ish_suspend),
+};
 
 static ssize_t base_version_show(struct device *cdev,
 				 struct device_attribute *attr, char *buf)
-- 
2.43.0