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Date:   Wed, 13 Jul 2022 13:18:05 -0500
From:   Bjorn Helgaas <helgaas@kernel.org>
To:     Ajay Garg <ajaygargnsit@gmail.com>,
        Kishon Vijay Abraham I <kishon@ti.com>
Cc:     linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: No controller seen in /sys/kernel/config/pci_ep/controllers
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[+to Kishon, endpoint maintainer, +cc LKML]

On Wed, Jul 13, 2022 at 12:53:06PM +0530, Ajay Garg wrote:
> Hello everyone.
> 
> The kernel has been built with :
> 
> ###################################
> CONFIG_PCI_ENDPOINT=y
> CONFIG_PCI_ENDPOINT_CONFIGFS=y
> CONFIG_PCI_EPF_TEST=y
> CONFIG_PCI_ENDPOINT_TEST=y
> ###################################
> 
> 
> Thereafter, following are seen :
> 
> ###################################
> $ sudo mount none /sys/kernel/config/ -t configfs
> mount: /sys/kernel/config: none already mounted or mount point busy.
> 
> $ ls -lrth /sys/class/pci_epc/
> total 0
> 
> $ ls -lrth /sys/kernel/config
> total 0
> drwxr-xr-x 4 root root 0 Jul 13 10:58 pci_ep
> drwxr-xr-x 2 root root 0 Jul 13 10:58 usb_gadget
> 
> $ ls -lrth /sys/kernel/config/pci_ep/functions
> total 0
> drwxr-xr-x 2 root root 0 Jul 13 10:58 pci_epf_test
> 
> $ ls -lrth /sys/kernel/config/pci_ep/controllers
> total 0
> 
> $
> ###################################
> 
> What is being missed?
> 
> Side Queries : Is the controller that is expected to be listed, a
> virtual-controller (like the one provided by CONFIG_USB_DUMMY_HCD in
> case of USB)?
> 
> Or there must be a real additional controller for pci-endpoint purpose?
> If yes, then :
> 
>               * I guess no listing is expected currently, as my machine has just
>                 one controller (as pci-host).
> 
>               * Is there a way to have an additional virtual pci-controller?
> 
> 
> Thanks and Regards,
> Ajay