[openib-general] [PATCH] mthca: restore missing registers

[Michael S. Tsirkin]

Quoting r. Roland Dreier <rdreier at cisco.com>:
> Subject: Re: [PATCH] mthca: restore missing registers
> 
>     Michael> mthca misses restoring the following PCI-X/PCI-Express
>     Michael> registers at reset: PCI-X device: PCI-X command register
>     Michael> PCI-X bridge: upstream and downstream split transaction
>     Michael> registers PCI-Express : PCI-Express device control and
>     Michael> link control registers
> 
> Would it be simpler to just restore the full 256-byte PCI headers instead?

You can't do that - there are lots of registers where reading a value and then
writing it back has side effects.  Consider fields that are write 1 to clear, or
the VPD flag register. Further, there is no guarantee what writing fields
outside any capability list will do - consider the Tavor 22/23 debugging
registers as an example.

-- 
MST