Re: platform/x86: asus-wmi: SW_TABLET_MODE is always 1 on some devices

From: Hans de Goede
Date: Thu Sep 10 2020 - 13:51:36 EST

This is a multi-part message in MIME format. Hi,

On 9/4/20 7:17 PM, Samuel Čavoj wrote:

On 04.09.2020 12:06, Hans de Goede wrote:

On 9/4/20 11:45 AM, Samuel Čavoj wrote:

On 02.09.2020 14:52, Samuel Čavoj wrote:

On 02.09.2020 13:52, Hans de Goede wrote:
But I would rather try to figure out a better way. Can you
create an acpidump, by as root running:

acpidump -o acpidump.asus-UX360CA

The file is attached gzipped.

And then send me a direct (so without including the list)
email with the generated acpidump.asus-UX360CA file attached please?

Also, if necessary are you capable of building your own
kernel with a (test)patch applied ?

Yes, that is no problem at all.
Thank you for your quick response.


I don't mean to waste your time, it's just that my trust in mail systems
has been steadily decreasing. I would just like to make sure you have
received my previous email with the acpidump.

In case not, here[1] it is available over https, if the message got
dropped because of the attachment.

I got your mail, but I've been burried under a ton of work,
so it may take a couple of days at least before I can take
a closer look at this.

That's quite alright.

I decided I would try and see if I can be of any use, so I looked around
in the WMI implementation in the DSDT and found the following in the
DSTS method:

37486 If ((IIA0 == 0x00120063))
37487 {
37488 Local0 = ^^PCI0.LPCB.EC0.DKPS ()
37489 If ((Local0 == One))
37490 {
37491 Return (0x00010001)
37492 }
37493 Else
37494 {
37495 Return (0x00010000)
37496 }
37497 }

This is the If statement responsible for the ASUS_WMI_DEVID_KBD_DOCK
device, and it always seems to return 0x00010000 on my machine. I
followed it up the call chain but in the end it just read some bit from
some register of the EC.

Then I noticed the If statement right above it, which corresponds to
dev_id 0x00060062:

37472 If ((IIA0 == 0x00060062))
37473 {
37474 If (^^PCI0.LPCB.EC0.RPIN (0x15))
37475 {
37476 Local0 = 0x00010001
37477 }
37478 Else
37479 {
37480 Local0 = 0x00010000
37481 }
37483 Return (Local0)
37484 }

By a stroke of luck, it turns out it's the correct one! I patched the
driver to query the state on every event and print it out, and it is
exactly what we are looking for.

The state is 0 if the device is in normal, laptop state and changes to 1
if flipped over 180 degrees. I patched the module so that the
SW_TABLET_MODE switch was set according to it, and everything seems to
be behaving as it should.

Good work on figuring this out!

This is, of course, not a full solution, as we
still somehow need to decide whether to use the KDB_DOCK device or this
one. I don't know what to do about that. Ideally find some flag in the
ACPI which says which one we should use?

The event code which is fired when the lid switch state changes, as we
already know from the sparse keymap[1], is 0xfa. When the laptop is
suspended in laptop mode, flipped to tablet mode in its sleep and
awoken, the event is fired. It is, however, not fired when doing it the
other way around, so we should probably check the state on resume as

Ok, I've written a patch to try and use the 0x00060062 WMI object/devid
first and only if that is not there use the 0x00120063 one which the
Bay Trail and Cherry Trail devices use.

I've attached the patch, please give it a try.




I did successfully receive your acpidump, thanks.