RE: Dell docking station & Dell Embedded Controller & PS/2 devices

-----Original Message-----
From: Pali Rohár [mailto:pali.rohar@gmail.com]
Sent: Monday, May 7, 2018 3:28 PM
To: Limonciello, Mario
Cc: dmitry.torokhov@gmail.com; linux-input@vger.kernel.org; linux-
kernel@vger.kernel.org
Subject: Re: Dell docking station & Dell Embedded Controller & PS/2 devices

On Monday 07 May 2018 20:18:30 Mario.Limonciello@dell.com wrote:

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So I guess you could write a platform driver that would install i8042
filter on Dell laptops/portables, monitor keyboard data stream and kick
of rescans on serio ports. The problem is filter gets "serio" so you do
not really know whether ACK is spurious or not. And I would really
prefer keeping this crap out of atkbd proper... And all of this is racy
as hell. What happens if we get keyboard reconnected as we reinitialize
it?

If it's done as a platform driver I would suspect it's possible to tell whether
a dock is connected to at least give you some heuristic here to have a better
guess whether it's spurious.

Apparently checking for docking station is not enough. There are also
Dell Legacy Extenders (or how it is called) which exports internal PS/2,
Parallel and Serial Ports. It is also connecting to bottom of laptop.
But currently I do not have them for testing.

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Pali on your system that supports this dock, check and see how many
System Enclosure SMBIOS tables (structure type 03) are present.

Do you mean DMI type 3 structure? Here is something from dmidecode:

Handle 0x0003, DMI type 3, 22 bytes
Chassis Information
        Manufacturer: Dell Inc.
        Type: Laptop
        Lock: Not Present
        Version: Not Specified
        Serial Number: --REMOVED--
        Asset Tag: Not Specified
        Boot-up State: Safe
        Power Supply State: Safe
        Thermal State: Safe
        Security Status: None
        OEM Information: 0x00000000
        Height: Unspecified
        Number Of Power Cords: 1
        Contained Elements: 0
        SKU Number: To be filled by O.E.M.

But probably you mean something different?

Plug in your dock before you boot up and see if you have a second structure like
that type produced.

I already started docked laptop via dock power button. And in dmidecode
output is only one DMI type 3 block.

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If not, then I guess this isn't a reliable way to find the dock
on that system and I'll have to see if there is another.

Seems not. Also detection of dock should work also when you connect
laptop at system runtime, not only when connected prior to booting.

The items that show up in this structure are supposed to be dynamic
values but static addresses.  I was asking to check before bootup in 
case this was a problem of Linux caching SMBIOS table information once.
The values I was referring to might be for older generation dock though,
I'll see if I can find anything else you can check.