Re: Linux 2.6.20-rc6 - sky2 resume breakage

[Stephen Hemminger <shemminger@linux-foundation.org>]

On Mon, 29 Jan 2007 14:37:23 -0800 (PST)
Linus Torvalds <torvalds@linux-foundation.org> wrote:

> 
> 
> On Mon, 29 Jan 2007, Thomas Gleixner wrote:
> > 
> > Reverting commit 44ade178249fe53d055fd92113eaa271e06acddd, which added
> > this hackery in the first place, makes the device survive
> > suspend/resume.
> 
> I suspect some BIOSes do *not* screw up the MSI thing on resume, and 
> others do.
> 
> I would suggest that the real fix is to not do that kind of hackery at 
> suspend/resume time (because we can't know what the heck the BIOS does), 
> and instead just do one of two cases:
> 
>  - since MSI is known to be broken for the sky2 driver due to firmware 
>    bugs, just disable it by default if CONFIG_PM is enabled. The 
>    advantages of MSI just aren't all that compelling. Possibly add a 
>    command line option to force MSI to be enabled regardless.

MSI works fine for almost all systems (except AMD systems where
MSI is broken for ALL devices).

>    Simple, direct, and should work for everybody.
> 
>  - Just add a command line to disable MSI for people that it breaks for. 
> 
>    I don't actually like this one. It defaults to the unsafe behaviour, 
>    and while that makes sense in a "well, your machine is broken anyway" 
>    kind of way, the thing is, the advantages of MSI just aren't big enough 
>    to warrant defaulting to a known-unsafe thing, even if only a small 
>    percentage of machines are affected.

Module option out already exists.