Re: [PATCH] ACPI / LPSS: Don't abort acpi scan on missing mem resource.

["Life is hard, and then you die" <ronald@innovation.ch>]

On Mon, Aug 07, 2017 at 01:47:09PM +0300, Mika Westerberg wrote:
> On Fri, Aug 04, 2017 at 04:46:16PM -0700, Ronald Tschalär wrote:
> > On MacBook8's (2015) there appears to be no memory resource for the
> > SPI master device. Returning an error here in this case then leads to
> > the acpi device being ignored completely instead of just the handler
> > being skipped.
> 
> What's the problem if we prevent creation of the SPI master device? How
> does user see the issue?

Their keyboard and touchpad don't work :-)

> It is not like the SPI driver could use the
> device anyway.

The spi master device works just fine (once recognized). Nothing the
acpi-lpss handler provides appears to be necessary for this device
(though admittedly the PM stuff hasn't been explored much).

> Just trying to understand why we would want to change the behaviour.

Apologies for the lack of context. This is related to the work on
the SPI keyboard and touchpad driver for MacBook(Pro)'s
(https://github.com/cb22/macbook12-spi-driver/) (and as such is
tangentally related to the recent apple SPI properties work by Lukas
Wunner that just got accepted). We obviously need the spi master
device in order to set up the keyboard/touchpad SPI slave device.

Btw., in case it matters, this SPI controller shows up in lscpi as

  00:15.4 Serial bus controller [0c80]: Intel Corporation Wildcat Point-LP Serial IO GSPI Controller #1 [8086:9ce6] (rev 03)

Hope this helps.


  Cheers,

  Ronald