linux-kernel - Re: [PATCH] HID: i2c-hid: add polling mode based on connected GPIO chip's pin status

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Message-ID: <20201016143200.tev62sbttbac5kci@Rk>
Date:   Fri, 16 Oct 2020 22:32:00 +0800
From:   Coiby Xu <coiby.xu@...il.com>
To:     Barnabás Pőcze <pobrn@...tonmail.com>
Cc:     "linux-input@...r.kernel.org" <linux-input@...r.kernel.org>,
        Jiri Kosina <jikos@...nel.org>,
        Benjamin Tissoires <benjamin.tissoires@...hat.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] HID: i2c-hid: add polling mode based on connected GPIO
 chip's pin status

Hi Barnabás,

Thank you for reviewing theis patch! I've Cced a new version to you.

On Thu, Oct 15, 2020 at 10:33:50AM +0000, Barnabás Pőcze wrote:
>Hi,
>
>I believe this patch causes I2C HID devices not to work with IRQs after resuming
>from suspend.
>
>
>> [...]
>>  #ifdef CONFIG_PM_SLEEP
>> @@ -1183,7 +1292,8 @@ static int i2c_hid_suspend(struct device *dev)
>>  	/* Save some power */
>>  	i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
>>
>> -	disable_irq(client->irq);
>> +	if (polling_mode == I2C_POLLING_DISABLED)
>> +		disable_irq(client->irq);
>>
>
>The IRQ is disabled when suspending if polling is *off*.
>
>
>>  	if (device_may_wakeup(&client->dev)) {
>>  		wake_status = enable_irq_wake(client->irq);
>> @@ -1216,7 +1326,7 @@ static int i2c_hid_resume(struct device *dev)
>>
>>  		if (ihid->pdata.post_power_delay_ms)
>>  			msleep(ihid->pdata.post_power_delay_ms);
>> -	} else if (ihid->irq_wake_enabled) {
>> +	} else if (ihid->irq_wake_enabled && polling_mode != I2C_POLLING_DISABLED) {
>
>As a side note, I'm not sure if the 'polling_mode != I2C_POLLING_DISABLED' part
>is necessary (or that it's necessary *here*). It causes 'i2c_hid_resume' and
>'i2c_hid_suspend' to be "asymmetric" which - I believe - may cause problems.
>
>
>>  		wake_status = disable_irq_wake(client->irq);
>>  		if (!wake_status)
>>  			ihid->irq_wake_enabled = false;
>> @@ -1225,7 +1335,8 @@ static int i2c_hid_resume(struct device *dev)
>>  				wake_status);
>>  	}
>>
>> -	enable_irq(client->irq);
>> +	if (polling_mode != I2C_POLLING_DISABLED)
>> +		enable_irq(client->irq);
>>
>
>The IRQ is enabled when resuming if polling is *on*. It should be enabled if polling is *off*
>in my opinion.
>
>
>> [...]
>
>
>Regards,
>Barnabás Pőcze

--
Best regards,
Coiby