On Wed, Jul 19, 2017 at 04:20:12PM +0300, Aleksandr Bezzubikov wrote:
> Now PCI bridges (and PCIE root port too) get a bus range number in system init,
> basing on currently plugged devices. That's why when one wants to hotplug another bridge,
> it needs his child bus, which the parent is unable to provide.
Could you explain how you trigger this?
I'm trying to hot plug pcie-pci bridge into pcie root port, and Linux says 'cannot allocate bus number for device bla-bla'. This obviously does not allow me to use the bridge at all.
> The suggested workaround is to have vendor-specific capability in RedHat generic pcie-root-port
> that contains number of additional bus to reserve on BIOS PCI init.
But wouldn't the proper fix be for the PCI bridge to have the subordinate
value be extended to fit more bus ranges?
What do you mean? This is what I'm trying to do. Do you suppose to get rid of vendor-specific cap and use original register value instead of it?
>
> Aleksandr Bezzubikov (2):
> pci: add support for direct usage of bdf for capability lookup
> pci: enable RedHat pci bridges to reserve more buses
>
> src/fw/pciinit.c | 12 ++++++++++--
> src/hw/pcidevice.c | 24 ++++++++++++++++++++++++
> src/hw/pcidevice.h | 1 +
> 3 files changed, 35 insertions(+), 2 deletions(-)
>
> --
> 2.7.4
>
>