linux-kernel - Re: [PATCH] i2c: designware: Add disable runtime pm quirk

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Date:   Wed, 26 Jun 2019 09:27:27 +0300
From:   Jarkko Nikula <jarkko.nikula@...ux.intel.com>
To:     AceLan Kao <acelan.kao@...onical.com>
Cc:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        linux-i2c@...r.kernel.org,
        "Linux-Kernel@...r. Kernel. Org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] i2c: designware: Add disable runtime pm quirk

On 6/26/19 5:32 AM, AceLan Kao wrote:
> Adding I2C_HID_QUIRK_NO_RUNTIME_PM quirk doesn't help on this issue.
> Actually, Goodix touchpad already has that PM quirk in the list for other issue.
>          { I2C_VENDOR_ID_GOODIX, I2C_DEVICE_ID_GOODIX_01F0,
>                 I2C_HID_QUIRK_NO_RUNTIME_PM },
> I also modify the code as you suggested, but no luck.
> 
Yeah, I realized it won't help as the i2c-hid device is anyway powered 
on constantly when the device is open by the pm_runtime_get_sync() call 
in i2c_hid_open().

> It's not Goodix takes time to wakeup, it's designware I2C controller.
> Designware doesn't do anything wrong here, it's Goodix set the interrupt timeout
> that leads to the issue, so we have to prevent designware from runtime
> suspended.
> But only on that bus where Goodix is connected and open by user space. 
What I mean something like below:

diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c 
b/drivers/hid/i2c-hid/i2c-hid-core.c
index 90164fed08d3..bbeaa39ddc23 100644
--- a/drivers/hid/i2c-hid/i2c-hid-core.c
+++ b/drivers/hid/i2c-hid/i2c-hid-core.c
@@ -795,6 +795,9 @@ static int i2c_hid_open(struct hid_device *hid)
  	struct i2c_hid *ihid = i2c_get_clientdata(client);
  	int ret = 0;

+	/* some quirk test here */
+	pm_runtime_get_sync(&client->adapter->dev);
+
  	ret = pm_runtime_get_sync(&client->dev);
  	if (ret < 0)
  		return ret;
@@ -812,6 +815,9 @@ static void i2c_hid_close(struct hid_device *hid)

  	/* Save some power */
  	pm_runtime_put(&client->dev);
+
+	/* some quirk test here */
+	pm_runtime_put(&client->adapter->dev);
  }

  static int i2c_hid_power(struct hid_device *hid, int lvl)

-- 
Jarkko