Re: ACPI defined devices not showing up under /sys/bus/platform/devices

[Mika Westerberg <mika.westerberg@linux.intel.com>]

On Thu, Sep 18, 2014 at 02:04:11PM +0200, Hans de Goede wrote:
> Hi,
> 
> I'm trying to help various users with Asus X450 and Asus X550 laptops
> to get their touchpad to work:
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=1110011
> 
> We believe that this touchpad is connected over i2c, using the
> i2c-designware-platform driver.
> 
> If you look at the DSDT attached there you can clearly see
> nodes defines which should lead to e.g. :
> 
> /sys/bus/platform/devices/INT33C2:00
> 
> Showing up (which should then be bound by i2c-designware-platform).
> 
> But nothing is showing up, not a single ACPI defined device shows
> up actually:
> 
> 
> 
> 
> 
> [root@asusx550 devices]# ll
> insgesamt 0
> lrwxrwxrwx. 1 root root 0 22. Jul 14:56 alarmtimer -> ../../../devices/platform/alarmtimer
> lrwxrwxrwx. 1 root root 0 25. Jul 23:54 asus-nb-wmi -> ../../../devices/platform/asus-nb-wmi
> lrwxrwxrwx. 1 root root 0 25. Jul 23:54 coretemp.0 -> ../../../devices/platform/coretemp.0
> lrwxrwxrwx. 1 root root 0 22. Jul 14:56 efi-framebuffer.0 -> ../../../devices/platform/efi-framebuffer.0
> lrwxrwxrwx. 1 root root 0 22. Jul 14:56 Fixed MDIO bus.0 -> ../../../devices/platform/Fixed MDIO bus.0
> lrwxrwxrwx. 1 root root 0 22. Jul 14:56 i8042 -> ../../../devices/platform/i8042
> lrwxrwxrwx. 1 root root 0 25. Jul 23:54 iTCO_wdt -> ../../../devices/pci0000:00/0000:00:1f.0/iTCO_wdt
> lrwxrwxrwx. 1 root root 0 25. Jul 23:54 microcode -> ../../../devices/platform/microcode
> lrwxrwxrwx. 1 root root 0 22. Jul 14:56 pcspkr -> ../../../devices/platform/pcspkr
> lrwxrwxrwx. 1 root root 0 25. Jul 23:54 regulatory.0 -> ../../../devices/platform/regulatory.0
> lrwxrwxrwx. 1 root root 0 25. Jul 23:54 rtsx_pci_ms.0 -> ../../../devices/pci0000:00/0000:00:1c.2/0000:02:00.0/rtsx_pci_ms.0
> lrwxrwxrwx. 1 root root 0 25. Jul 23:54 rtsx_pci_sdmmc.0 -> ../../../devices/pci0000:00/0000:00:1c.2/0000:02:00.0/rtsx_pci_sdmmc.0
> lrwxrwxrwx. 1 root root 0 22. Jul 14:56 serial8250 -> ../../../devices/platform/serial8250
> 
> 
> Which is weird, since any recent machine usually has at least one or 2
> show up.

It depends whether the BIOS has enabled those or not.

If

 # cat /sys/bus/acpi/devices/INT33C2:00/status
 # cat /sys/bus/acpi/devices/INT33C3:00/status

returns 0xf, then the device should be there, otherwise it is not.

The "status" refers directly shat _STA() ACPI method returns.

Note that the device could also be in PCI mode, in case lspci should
show it.