[PATCH v4 1/2] cxl: Set the PBCQ Tunnel BAR register when enabling capi mode

[Michael Ellerman]

Philippe Bergheaud <felix at linux.ibm.com> writes:

> Skiboot used to set the default Tunnel BAR register value when capi mode
> was enabled. This approach was ok for the cxl driver, but prevented other
> drivers from choosing different values.
>
> Skiboot versions > 5.11 will not set the default value any longer. This
> patch modifies the cxl driver to set/reset the Tunnel BAR register when
> entering/exiting the cxl mode, with pnv_pci_set_tunnel_bar().
>
> That should work with old skiboot (since we are re-writing the value
> already set) and new skiboot.

But doesn't that mean new skiboot can't boot any old kernel? That seems
undesirable.

cheers