Re: new SBus related DMA warnings in 4.18+git

Christoph Hellwig
2018-08-28T09:24:32Z

On Mon, Aug 27, 2018 at 01:41:36PM -0700, David Miller wrote:
> From: Sam Ravnborg <sam-uyr5N9Q2VtJg9hUCZPvPmw@public.gmane.org>
> Date: Mon, 27 Aug 2018 21:15:18 +0200
>
> > Why not fix the drivers rather than papering over the fact
> > that they are missing the DMA mask?
> >
> > We are in the lucky situation the Meelis can test any patches.
>
> SBUS drivers never set the mask because they never needed to and could
> use the default, since SBUS IOMMUs were quite universal in nature.

In addition to that the historical expectation is that you can do
dma to platform_devices without setup, and for some reason sbus
devices all show up as platform_devices.

> I think it's more error prone to add the mask setting to every single
> SBUS driver than to just have the core setup the default properly.