linux-kernel - Re: [PATCH] ELAN touchpad i2c

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Message-Id: <DDBA2E60-2658-413B-969A-59DD1AFB0536@canonical.com>
Date:   Thu, 21 Mar 2019 17:28:15 +0800
From:   Kai Heng Feng <kai.heng.feng@...onical.com>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     Hans de Goede <hdegoede@...hat.com>,
        Benjamin Tissoires <benjamin.tissoires@...hat.com>,
        hotwater438@...anota.com, Jiri Kosina <jikos@...nel.org>,
        Stephen Boyd <swboyd@...omium.org>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Dmitry Torokhov <dtor@...omium.org>,
        "open list:HID CORE LAYER" <linux-input@...r.kernel.org>,
        lkml <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ELAN touchpad i2c_hid bugs fix



> On Mar 21, 2019, at 4:55 PM, Andy Shevchenko <andy.shevchenko@...il.com> wrote:
> 
> On Thu, Mar 21, 2019 at 6:08 AM Kai-Heng Feng
> <kai.heng.feng@...onical.com> wrote:
>> at 01:18, Andy Shevchenko <andy.shevchenko@...il.com> wrote:
>>> On Wed, Mar 20, 2019 at 6:55 PM Kai-Heng Feng
>>> <kai.heng.feng@...onical.com> wrote:
>>>> at 23:39, Hans de Goede <hdegoede@...hat.com> wrote:
>>>>> On 3/20/19 3:37 PM, Benjamin Tissoires wrote:
> 
>>>> Recently we found that Elan touchpad doesn’t like GpioInt() from its _CRS.
>>>> Once the Interrupt() is used instead, the issue goes away.
>>> 
>>> IIRC i2c core tries to get interrupt from Interrupt() resource and
>>> then falls back to GpioInt().
>>> See i2c_acpi_get_info() and i2c_device_probe().
>> 
>> Here’s its ASL:
> 
>>             Name (SBFB, ResourceTemplate ()
>>             {
>>                 I2cSerialBusV2 (0x002C, ControllerInitiated, 0x00061A80,
>>                     AddressingMode7Bit, "\\_SB.PCI0.I2C4",
>>                     0x00, ResourceConsumer, , Exclusive,
>>                     )
>>             })
>>             Name (SBFG, ResourceTemplate ()
>>             {
>>                 GpioInt (Level, ActiveLow, ExclusiveAndWake, PullUp, 0x0000,
>>                     "\\_SB.GPO1", 0x00, ResourceConsumer, ,
>>                     )
>>                     {   // Pin list
>>                         0x0012
>>                     }
>>             })
>>             Name (SBFI, ResourceTemplate ()
>>             {
>>                 Interrupt (ResourceConsumer, Level, ActiveLow, ExclusiveAndWake, ,, )
>>                 {
>>                     0x0000003C,
>>                 }
>>             })
> 
>>             Method (_CRS, 0, NotSerialized)  // _CRS: Current Resource Settings
>>             {
> 
>>                 If ((OSYS < 0x07DC))
>>                 {
>>                     Return (SBFI) /* \_SB_.PCI0.I2C4.TPD0.SBFI */
>>                 }
> 
> This will return only Interrupt() resource
> 
>> 
>>                 Return (ConcatenateResTemplate (SBFB, SBFG))
> 
> This one I2cSerialBus() and GpioInt().
> 
>>             }
> 
> 
>>         }
>>     }
>> 
>> Change SBFG to SBFI in its _CRS can workaround the issue.
>> Is ASL in this form possible to do the flow you described?
> 
> Since it's enumerated in Linux as I2C device, it means it gets I2C and
> GPIO resources.
> So, no, it's not possible.
> 
> What are you describing might tell us about one of the following:
> - touchpad should be switched to PS/2 mode in order to get working
> - GPIO resource is not correct / bug in GPIO driver
> 
> I don't believe the first one is a case here.
> If GPIO resource is not correct and main OS has some quirks, we need
> to do similar in Linux.

How do I check quirks on Windows?

> Otherwise, debugging GPIO driver, starting from what exactly (pin
> number, pin settings, etc) gets i2c-hid module.

Ok, please let me know where should I start looking into.

> 
> Note, ACPICA and related stuff is done in order to be Windows compatible.
> If you have settings in BIOS that defines OS to boot, it should be
> chosen Windows.

Yes, it’s Windows.

Kai-Heng

> 
> -- 
> With Best Regards,
> Andy Shevchenko