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From:   Kai-Heng Feng <kai.heng.feng@canonical.com>
To:     hdegoede@redhat.com, mgross@linux.intel.com
Cc:     Kai-Heng Feng <kai.heng.feng@canonical.com>,
        Eric Piel <eric.piel@tremplin-utc.net>,
        Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org (open list),
        platform-driver-x86@vger.kernel.org (open list:X86 PLATFORM DRIVERS)
Subject: [PATCH] platform/x86: hp_accel: Avoid invoking _INI to speed up resume
Date:   Fri, 30 Apr 2021 14:07:35 +0800
Message-Id: <20210430060736.590321-1-kai.heng.feng@canonical.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

hp_accel can take almost two seconds to resume on some HP laptops.

The bottleneck is on evaluating _INI, which is only needed to run once.

Resolve the issue by only invoking _INI when it's necessary. Namely, on
probe and on hibernation restore.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
 drivers/misc/lis3lv02d/lis3lv02d.h |  1 +
 drivers/platform/x86/hp_accel.c    | 22 +++++++++++++++++++++-
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/lis3lv02d/lis3lv02d.h b/drivers/misc/lis3lv02d/lis3lv02d.h
index c394c0b08519a..7ac788fae1b86 100644
--- a/drivers/misc/lis3lv02d/lis3lv02d.h
+++ b/drivers/misc/lis3lv02d/lis3lv02d.h
@@ -271,6 +271,7 @@ struct lis3lv02d {
 	int			regs_size;
 	u8                      *reg_cache;
 	bool			regs_stored;
+	bool			init_required;
 	u8                      odr_mask;  /* ODR bit mask */
 	u8			whoami;    /* indicates measurement precision */
 	s16 (*read_data) (struct lis3lv02d *lis3, int reg);
diff --git a/drivers/platform/x86/hp_accel.c b/drivers/platform/x86/hp_accel.c
index 799cbe2ffcf36..8c0867bda8280 100644
--- a/drivers/platform/x86/hp_accel.c
+++ b/drivers/platform/x86/hp_accel.c
@@ -88,6 +88,9 @@ MODULE_DEVICE_TABLE(acpi, lis3lv02d_device_ids);
 static int lis3lv02d_acpi_init(struct lis3lv02d *lis3)
 {
 	struct acpi_device *dev = lis3->bus_priv;
+	if (!lis3->init_required)
+		return 0;
+
 	if (acpi_evaluate_object(dev->handle, METHOD_NAME__INI,
 				 NULL, NULL) != AE_OK)
 		return -EINVAL;
@@ -356,6 +359,7 @@ static int lis3lv02d_add(struct acpi_device *device)
 	}
 
 	/* call the core layer do its init */
+	lis3_dev.init_required = true;
 	ret = lis3lv02d_init_device(&lis3_dev);
 	if (ret)
 		return ret;
@@ -403,11 +407,27 @@ static int lis3lv02d_suspend(struct device *dev)
 
 static int lis3lv02d_resume(struct device *dev)
 {
+	lis3_dev.init_required = false;
+	lis3lv02d_poweron(&lis3_dev);
+	return 0;
+}
+
+static int lis3lv02d_restore(struct device *dev)
+{
+	lis3_dev.init_required = true;
 	lis3lv02d_poweron(&lis3_dev);
 	return 0;
 }
 
-static SIMPLE_DEV_PM_OPS(hp_accel_pm, lis3lv02d_suspend, lis3lv02d_resume);
+static const struct dev_pm_ops hp_accel_pm = {
+	.suspend = lis3lv02d_suspend,
+	.resume = lis3lv02d_resume,
+	.freeze = lis3lv02d_suspend,
+	.thaw = lis3lv02d_resume,
+	.poweroff = lis3lv02d_suspend,
+	.restore = lis3lv02d_restore,
+};
+
 #define HP_ACCEL_PM (&hp_accel_pm)
 #else
 #define HP_ACCEL_PM NULL
-- 
2.30.2