[Intel-gfx] [PATCH] drm/i915: force full modeset if the connector is in DPMS OFF mode

[Imre Deak]

On Fri, 2013-05-03 at 12:44 +0100, Chris Wilson wrote:
> On Fri, May 03, 2013 at 02:22:09PM +0300, Imre Deak wrote:
> > Currently the driver's assumed behavior for a modeset with an attached
> > FB is that the corresponding connector will be switched to DPMS ON mode
> > if it happened to be in DPMS OFF (or another power save mode). This
> > wasn't enforced though if only the FB changed, everything else (format,
> > connector etc.) remaining the same. In this case we only set the new FB
> > base and left the connector in the old power save mode.
> > 
> > Fix this by forcing a full modeset whenever there is an attached FB and
> > any affected connector is in a power save mode.
> > 
> > Signed-off-by: Imre Deak <imre.deak at intel.com>
> 
> NAK. Papering over bugs, much?

Ok. I posted this based on our IRC discussion where we seemed to agree
that DPMS_ON is assumed already; just that it's not done consistently.
That is if user space does a modeset now that ends up in a full modeset
(lets say a new FB with different format) then the kernel will do a
DPMS_ON. But if the new FB happens to be the same format then it won't.
I thought this is inconsistent and should be fixed.

Another way to make it consistent would be then to remove DPMS ON from
the full modeset path..

--Imre