Re: [PATCH 1/1] thunderbolt: Prevent root port runtime suspend during NVM upgrade

[Greg Kroah-Hartman]

On Mon, Nov 26, 2018 at 12:47:46PM +0300, Mika Westerberg wrote:
> During NVM upgrade process the host router is hot-removed for a short
> while. During this time it is possible that the root port is moved into
> D3cold which would be fine if the root port could trigger PME on itself.
> However, many systems actually do not implement it so what happens is
> that the root port goes into D3cold and never wakes up unless userspace
> does PCI config space access, such as running 'lscpi'.
> 
> For this reason we explicitly prevent the root port from runtime
> suspending during NVM upgrade.
> 
> Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
> ---
>  drivers/thunderbolt/switch.c | 40 ++++++++++++++++++++++++++++++++++--
>  1 file changed, 38 insertions(+), 2 deletions(-)

Is this a regression?  If so, should it go to stable kernels?

If not, and this never worked, should this just wait until 4.21-rc1?

thanks,

greg k-h