Re: Assign BAR address for pci device after hotplug

[Greg KH <greg@kroah.com>]

A: Top-posting.
Q: What is the most annoying thing in e-mail?

A: No.
Q: Should I include quotations after my reply?

http://daringfireball.net/2007/07/on_top

On Tue, Aug 09, 2016 at 10:00:22AM -0700, divakar wrote:
> Hi ,
> 
> The modified probe function was the one with the pci_reassign_resource 
> function. 

Don't do that.  That's for the pci core to use only.


> 
> modified_my_driver_probe:
> static int my_probe(struct pci_dev *pdev, const struct pci_device_id 
> *id)
> {
>  
>         /* Enable hotplug support
>            TODO: Check if this is right way to do it */
>         if( pci_resource_start (pdev,0) <= 0) {
>                 ret = pci_assign_resource(pdev,0);
>                 if( 0 > ret) {
>                         dev_err(&pdev->dev, " Failed to assign resource 
> \n");
>                         return ret;
>                 }
>         }
> 
>         ret = pci_enable_device(pdev);
> 
> }
> 
> Thanks for your comments on the hardware. I hope my previous message 
> with the output log snippets came through. My observation of the events 
> happening seem to suggest there is a hotplug controller as i can see the 
> difference between with and without enabling "pciehp". Also 
> pci_resource_start in the probe function of the endpoint device driver 
> seem to work. Hence my persistence in understanding the behavior. 

If the pciehp driver does not bind to your hardware, then it will not
work properly.

Again, PCI hotplug requires a PCI hotplug controller, or special
firmware/bios support for it.  You can't do it properly without it, read
the specification for all of the nasty details.

good luck!

greg k-h