[Intel-gfx] [DRM/I915]: Restore the modeset for every activated CRTC

[yakui]

On Thu, 2009-07-02 at 15:43 +0800, Zhenyu Wang wrote:
> On 2009.07.02 15:16:56 +0800, yakui.zhao at intel.com wrote:
> > From: Zhao Yakui <yakui.zhao at intel.com>
> > 
> > Restore the modeset for every activated CRTC in course of resume.
> > This is realized by calling the function of drm_helper_resume_force_mode.
> > Note: it is meaningful only for the KMS mode.
> > 
> > Signed-off-by: Zhao Yakui <yakui.zhao at intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_drv.c |    5 +++++
> >  1 file changed, 5 insertions(+)
> > 
> > Index: linux-2.6/drivers/gpu/drm/i915/i915_drv.c
> > ===================================================================
> > --- linux-2.6.orig/drivers/gpu/drm/i915/i915_drv.c	2009-07-02 14:24:44.000000000 +0800
> > +++ linux-2.6/drivers/gpu/drm/i915/i915_drv.c	2009-07-02 14:25:52.000000000 +0800
> > @@ -35,6 +35,7 @@
> >  
> >  #include "drm_pciids.h"
> >  #include <linux/console.h>
> > +#include "drm_crtc_helper.h"
> >  
> >  static unsigned int i915_modeset = -1;
> >  module_param_named(modeset, i915_modeset, int, 0400);
> > @@ -115,6 +116,10 @@
> >  
> >  		drm_irq_install(dev);
> >  	}
> > +	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
> > +		/* Resume the modeset for every activated CRTC */
> > +		drm_helper_resume_force_mode(dev);
> > +	}
> 
> It can be folded into the if before, and with this one, do we still need save/restore?
Yes. It can be folded into the if before. But it seems more clear that
it has its own. 

When we set the mode for one connector, the modeinfo will be stored in
the corresponding crtc. The modeinfo won't be changed until we set the
mode again.

Maybe the modesetting is changed by BIOS in course of suspend/resume.
So we will restore the previous modesetting for activaated crtc in
course of resume. This is to assure the previous modesetting.
Thanks.
> 
> >  
> >  	return ret;
> >  }
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>