How to find a device based on its device ID

th flag

Recently I had a problem that one of the USB ports was stopping Ubuntu 20.04 from suspending. It was suspending, but in a split of the second started again.

I found in several posts (1, 2, 3) that it is possible to fix this by disabling a device in /proc/acpi/wakeup, but how to find which device stands behind each device code was not mentioned.

Device  S-state   Status   Sysfs node
PEG0      S4    *enabled   pci:0000:00:01.0
PEGP      S4    *disabled  pci:0000:01:00.0
LID0      S3    *enabled   platform:PNP0C0D:01
RP01      S4    *disabled
PXSX      S4    *disabled
RP02      S4    *disabled
PXSX      S4    *disabled
RP03      S4    *disabled
PXSX      S4    *disabled
RP04      S4    *disabled
PXSX      S4    *disabled
RP05      S4    *enabled   pci:0000:00:1c.0
PXSX      S4    *disabled
RP06      S4    *disabled
PXSX      S4    *disabled
RP07      S4    *enabled   pci:0000:00:1c.6
PXSX      S4    *disabled  pci:0000:03:00.0
RP08      S4    *enabled   pci:0000:00:1c.7
PXSX      S4    *enabled   pci:0000:04:00.0
GLAN      S4    *disabled
EHC1      S3    *disabled  pci:0000:00:1d.0
EHC2      S3    *disabled  pci:0000:00:1a.0
XHC   S3    *disabled  pci:0000:00:14.0
TPD4      S4    *disabled
TPD7      S0    *disabled
TPD8      S0    *disabled
HDEF      S4    *disabled  pci:0000:00:1b.0

For me, problematic was EHC2 which is USB3.0 (echo EHC2 | sudo tee /proc/acpi/wakeup), but I found out about it after several trials of disable-suspend operations.

How can I find out what device is meant by these 3-4 character device IDs?

in flag

The device codes are vendor specific and are written in the DSDT (Differentiated System Description Table) inside the BIOS/UEFI. That said, there are some commonalities between the different manufacturers:

Name Device
EHCx / USBx USB 2.0 (EHCI) chip
GLAN Gigabit Ethernet
LID Laptop lid
PEGx PCI Express for Graphics slot #x
PS2K PS/2 keyboard
PS2M PS/2 mouse
PWRB / PBTN Power button
RP0x / EXPx PCIE slot #x (aka PCI Express Root Port #x)
XHC USB 3.0 (XHCI) chip

Any device not matching these patterns would need to be looked up in the technical documentation for the motherboard.


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