Re: Assign BAR address for pci device after hotplug

[divakar <divakar.chitturi@hpe.com>]

I don't doubt the truth in your comments about the HW. 
Unfortunately i have to work with the HW  i have and i am trying to find 
the best possible way to do this. I can certainly provide feedback for 
the next product/design based on the learnings from the current one.
At this point these cards are not expected to be plugged into different 
machine. So based on your statements if i can fake it i will take that 
path as a starter. Is there a writeup/documentation/eg which i can 
follow to understand the required steps? for now i have started looking 
at /drivers/pci/hotplug/* . 

Again thanks for your patience and time. 
Thanks


On Tuesday, August 09, 2016 08:59:43 PM Greg KH wrote:
> On Tue, Aug 09, 2016 at 11:48:59AM -0700, divakar wrote:
> > May be i missed one piece of information. I thought i had that in my
> > inline response but just realized i missed it.
> > 
> > Device 0 ( FPGA 0), has custom logic which will detect the presence
> > of the card 1 and card 2 and controls the power switches to the
> > same. So If this makes fpga0 a "hotplug controller " then i can add
> > the resource management logic/code for devices on card 1 and card 2
> > to this driver. Currently fpga_0 driver does some init for some of
> > the devices on itself. can i follow any hp controller driver
> > example to do the above or is there any specific driver/eg i can
> > follow? noted your point on reading the spec for the details and i
> > am on it.
> 
> You might get away with it for your limited hardware platform, but all
> bets are off if you plug it into something else.
> 
> Again, PCI resource management is handled by the firmware/bios and the
> pci hotplug controller.  You can try to fake it out, with limited
> success, but really, why do you want to do so?  Just use a real
> machine, that's what the pci hotplug hardware was designed for.  It's
> much cheaper than trying to work around it in the end, trust me...
> 
> greg k-h