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

[Jesse Barnes]

On Tue, 07 Jul 2009 11:40:10 -0700
Eric Anholt <eric at anholt.net> wrote:

> On Thu, 2009-07-02 at 15:16 +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);
> > +	}
> >  
> >  	return ret;
> >  }
> 
> So, this patch does a full modeset on top of the almost-full modeset
> done by the suspend/resume code.  That seems bogus -- if we're going
> to do this, we shouldn't do the rest of the save/restore for
> mdoesetting. However, note that drm_helper_resume_force_mode doesn't
> turn off disabled connectors, which seems wrong.

Yeah, that's one problem; I think the code should also be structured a
bit differently.  We really want to track whole KMS configurations
(output configuration and associated buffers), and have functions for
saving & restoring those (including forced restoration, e.g. for
lastclose or panic).  Right now the two uses are a bit muddled, which
means panic/lastclose can fail, and force_mode doesn't do the same
thing as a regular set_crtc call.

-- 
Jesse Barnes, Intel Open Source Technology Center