linux-kernel - Re: [PATCH] platform/x86: hp_accel: Avoid invoking

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Message-ID: <288b9b09-b7c7-4265-5eea-8fe7679fe4d1@tremplin-utc.net>
Date:   Sat, 8 May 2021 17:39:59 +0200
From:   Éric Piel <eric.piel@...mplin-utc.net>
To:     Kai-Heng Feng <kai.heng.feng@...onical.com>, hdegoede@...hat.com,
        mgross@...ux.intel.com
Cc:     Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        open list <linux-kernel@...r.kernel.org>,
        "open list:X86 PLATFORM DRIVERS" 
        <platform-driver-x86@...r.kernel.org>
Subject: Re: [PATCH] platform/x86: hp_accel: Avoid invoking _INI to speed up
 resume

On 30/04/2021 08:07, Kai-Heng Feng wrote:
> 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@...onical.com>

Although I'm listed as the maintainer, I don't have the hardware anymore 
to test. However, the changes seem fine to me.

Acked-by: Éric Piel <eric.piel@...mpplin-utc.net>

Best,
Éric

> ---
>   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
>