How to fix assert from ProcRRSetProviderOutputSource.

Dave Airlie airlied at
Tue Jun 10 18:54:04 PDT 2014

On 5 June 2014 22:59, Michal Srb <msrb at> wrote:
> Hi,
> When you have two graphic cards that both have Source Output and Sink Output
> capabilities (intel and nouveau for example). It's very easy to flip
> parameters of xrandr --setprovideroutputsource and attempt to provide outputs
> of the main screen to the slave screen.
> That triggers assert fault in:
>   ProcRRSetProviderOutputSource
>   xf86RandR14ProviderSetOutputSource
>   DetachUnboundGPU
>     assert(slave->isGPU);
> And whole X server crashes. I would like to fix it, but I am not sure what
> would be the best approach:
> 1) Add check to ProcRRSetProviderOutputSource and return BadValue when the
> provider is the main screen.

Seems like the best option.


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