Re: MSI and driver APIs

[Greg KH]

On Thu, Dec 15, 2005 at 02:38:12PM +1100, Benjamin Herrenschmidt wrote:
> So I want to start looking into separate implementation for powerpc, and
> based on what I come up with, find the commonalities and split the
> generic code.

That would be great, as it really is i386/x86-64 specific right now.

> However, there is at least one assumption that annoys me:
> 
> Currently, we assume that MSIs are disabled upon discovery of a device.
> That is, a driver probe() routine is called with MSIs off.
> 
> This is annoying on platforms with "intelligent" firmwares like POWER
> with hypervisor, as the firmware will have already configured MSIs for
> the full system & assigned them to devices.

If you are curious as to why this is, look at the lkml archives about a
month or two ago, where I tried to enable MSI by default.  It was a real
mess and caused way more problems than it tried to solve.

So, as David said, I don't think this is going to work out, sorry.

thanks,

greg k-h
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