Re: Problem with kernel rescan and realloc BAR resource for endponts

[Bjorn Helgaas <helgaas@kernel.org>]

On Thu, Apr 24, 2025 at 10:19:44PM +0530, Maverickk 78 wrote:
> Hello,
> 
> The command line parameter
> 
> pciehp.pciehp_force=1 pciehp.pciehp_debug=1 pcie_ports=native
> pci=nocrs pci=hpmemsize=256M,realloc pci=noacpi pci=realloc=on
> pci=nobios
> 
> 
> There are a couple of endpoints connected to downstream ports on a
> switch, and the endpoints are not visible during the BIOS (seabios)
> enumeration, but they are brought out of reset just before kernel
> starts pci scan.
> 
> Even though the kernel enumerates the endpoint with proper bdf and is
> able to read the config space but its not able to properly program the
> BAR register, the lspci lists as
> 
> 
> Region 0: Memory at <unassigned> (32-bit, non-prefetchable) [disabled]
> [size=32M]
> 
> 
> This is an emulation platform.

Can't really give any suggestions without seeing a complete dmesg log 
and output of "sudo lspci -vv".  This will give insight into how much
space the devices require and what space is available.

Bjorn