I cannot see my PCIe device in /sys/devices

rob18767 · 08-22-2017, 09:50 AM

Hi

I have a proprietary PCIe device that I can access through Ubuntu 32 bit V 16.10, with proprietary drivers that are operational.

Why can I not see the PCIe devices in /sys/devices but I can see it in /sys/bus/pci/devices?

jefro · 08-22-2017, 02:30 PM

No rule that a proprietary PCIe device has to report to buss I guess. (pretty sure on that)

Could be an oddity of the maker or faulty chip on it.

More ways to look at it. https://wiki.debian.org/HowToIdentifyADevice/PCI

Shadow_7 · 08-22-2017, 04:52 PM

It's more likely to show up with:

$ lspci -nnk

And /dev names are derived from /proc/devices plus minor numbers from /proc/misc for things who's major is 10. The /sys/ stuff is a relatively new kid on the block. Tab completion works in those parts, but things like "find" do not "find" the sub trees.

tofino_surfer · 08-25-2017, 07:29 PM

Quote:

I have a proprietary PCIe device that I can access through Ubuntu 32 bit V 16.10, with proprietary drivers that are operational.

Is this is an early PCIe SSD expansion card created before M.2 connectors and nmve support ?

Quote:

Why can I not see the PCIe devices in /sys/devices but I can see it in /sys/bus/pci/devices?

They are in /sys/devices in the /sys/devices/pci0000:00/ directory.

Code:

$ ll /sys/devices/pci0000:00/
total 0
drwxr-xr-x  3 root root    0 Aug 25 13:30 0000:00:00.0
drwxr-xr-x  8 root root    0 Aug 25 13:30 0000:00:01.0
drwxr-xr-x  3 root root    0 Aug 25 13:30 0000:00:02.0
drwxr-xr-x 12 root root    0 Aug 25 13:30 0000:00:16.0
drwxr-xr-x  5 root root    0 Aug 25 13:30 0000:00:1a.0
drwxr-xr-x  7 root root    0 Aug 25 13:30 0000:00:1b.0
drwxr-xr-x  4 root root    0 Aug 25 13:30 0000:00:1c.0
drwxr-xr-x  5 root root    0 Aug 25 13:30 0000:00:1c.3
drwxr-xr-x  5 root root    0 Aug 25 13:30 0000:00:1c.4
drwxr-xr-x  5 root root    0 Aug 25 13:30 0000:00:1c.5
drwxr-xr-x  5 root root    0 Aug 25 13:30 0000:00:1c.6
drwxr-xr-x  5 root root    0 Aug 25 13:30 0000:00:1c.7
drwxr-xr-x  5 root root    0 Aug 25 13:30 0000:00:1d.0
drwxr-xr-x  5 root root    0 Aug 25 13:30 0000:00:1f.0
drwxr-xr-x 10 root root    0 Aug 25 13:30 0000:00:1f.2
drwxr-xr-x  4 root root    0 Aug 25 13:30 0000:00:1f.3

The entries in /sys/bus/pci/devices/ are just symlinks to those entroes.

Code:

$ cd /sys/bus/pci/devices/
$ ll
total 0
lrwxrwxrwx 1 root root 0 Aug 25 13:30 0000:00:00.0 -> ../../../devices/pci0000:00/0000:00:00.0
lrwxrwxrwx 1 root root 0 Aug 25 13:30 0000:00:01.0 -> ../../../devices/pci0000:00/0000:00:01.0
lrwxrwxrwx 1 root root 0 Aug 25 13:30 0000:00:02.0 -> ../../../devices/pci0000:00/0000:00:02.0
lrwxrwxrwx 1 root root 0 Aug 25 13:30 0000:00:16.0 -> ../../../devices/pci0000:00/0000:00:16.0
lrwxrwxrwx 1 root root 0 Aug 25 13:30 0000:00:1a.0 -> ../../../devices/pci0000:00/0000:00:1a.0
lrwxrwxrwx 1 root root 0 Aug 25 13:30 0000:00:1b.0 -> ../../../devices/pci0000:00/0000:00:1b.0
lrwxrwxrwx 1 root root 0 Aug 25 13:30 0000:00:1c.0 -> ../../../devices/pci0000:00/0000:00:1c.0
lrwxrwxrwx 1 root root 0 Aug 25 13:30 0000:00:1c.3 -> ../../../devices/pci0000:00/0000:00:1c.3
lrwxrwxrwx 1 root root 0 Aug 25 13:30 0000:00:1c.4 -> ../../../devices/pci0000:00/0000:00:1c.4
lrwxrwxrwx 1 root root 0 Aug 25 13:30 0000:00:1c.5 -> ../../../devices/pci0000:00/0000:00:1c.5
lrwxrwxrwx 1 root root 0 Aug 25 13:30 0000:00:1c.6 -> ../../../devices/pci0000:00/0000:00:1c.6
lrwxrwxrwx 1 root root 0 Aug 25 13:30 0000:00:1c.7 -> ../../../devices/pci0000:00/0000:00:1c.7
lrwxrwxrwx 1 root root 0 Aug 25 13:30 0000:00:1d.0 -> ../../../devices/pci0000:00/0000:00:1d.0
lrwxrwxrwx 1 root root 0 Aug 25 13:30 0000:00:1f.0 -> ../../../devices/pci0000:00/0000:00:1f.0
lrwxrwxrwx 1 root root 0 Aug 25 13:30 0000:00:1f.2 -> ../../../devices/pci0000:00/0000:00:1f.2
lrwxrwxrwx 1 root root 0 Aug 25 13:30 0000:00:1f.3 -> ../../../devices/pci0000:00/0000:00:1f.3
lrwxrwxrwx 1 root root 0 Aug 25 13:30 0000:01:00.0 -> ../../../devices/pci0000:00/0000:00:01.0/0000:01:00.0
lrwxrwxrwx 1 root root 0 Aug 25 13:30 0000:01:00.1 -> ../../../devices/pci0000:00/0000:00:01.0/0000:01:00.1
lrwxrwxrwx 1 root root 0 Aug 25 13:30 0000:03:00.0 -> ../../../devices/pci0000:00/0000:00:1c.3/0000:03:00.0
lrwxrwxrwx 1 root root 0 Aug 25 13:30 0000:04:02.0 -> ../../../devices/pci0000:00/0000:00:1c.3/0000:03:00.0/0000:04:02.0
lrwxrwxrwx 1 root root 0 Aug 25 13:30 0000:05:00.0 -> ../../../devices/pci0000:00/0000:00:1c.4/0000:05:00.0
lrwxrwxrwx 1 root root 0 Aug 25 13:30 0000:06:00.0 -> ../../../devices/pci0000:00/0000:00:1c.5/0000:06:00.0
lrwxrwxrwx 1 root root 0 Aug 25 13:30 0000:07:00.0 -> ../../../devices/pci0000:00/0000:00:1c.6/0000:07:00.0
lrwxrwxrwx 1 root root 0 Aug 25 13:30 0000:08:00.0 -> ../../../devices/pci0000:00/0000:00:1c.7/0000:08:00.0

$ readlink -f 0000:00:1a.0
/sys/devices/pci0000:00/0000:00:1a.0
[andrew@server47 devices]
$ readlink -f 0000:01:00.0
/sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0

tofino_surfer · 08-26-2017, 11:35 AM

Quote:

No rule that a proprietary PCIe device has to report to buss I guess. (pretty sure on that)

Actually I am pretty sure that you just made that up. First of all there is no such thing as a "proprietary PCIe device" just a PCIe device that may use a proprietary storage protocol instead of standard SATA AHCI protocols.

Second PCIe devices don't "report to bus" they are scanned at boot time and return their vendor and product ids. The PCIe network can be rescanned in Linux later on as well. Although the driver protocol may be nonstandard every PCIe device needs to support the same basic PCIe interface otherwise it can't communicate on the PCIe network.

Quote:

Could be an oddity of the maker or faulty chip on it.

Actually the OP never said that only this device never showed up in /sys/... They were wondering why all PCIe devices couldn't be found in /sys/devices but I showed that they are.