On Wed, 29 Aug 2012 23:13:29 +0200 Daniel Vetter <daniel.vetter at ffwll.ch> wrote: > Since this only calls crtc helper functions, of which a shocking > amount are NULL. > > Now the curious thing is how the new modeset code worked with this > function call still present: > > Thanks to the hw state readout and the suspend fixes to properly > quiescent the register state, nothing is actually enabled at resume > (if the bios doesn't set up anything). Which means resume_force_mode > doesn't actually do anything and hence nothing blows up at resume > time. > > The other reason things do work is that the fbcon layer has it's own > resume notifier callback, which restores the mode. And thanks to the > force vt switch at suspend/resume, that then forces X to restore it's > own mode. > > Hence everything still worked (as long as the bios doesn't enable > anything). And we can just kill the call to resume_force_mode. > > The upside of both this patch and the preceeding patch to quiescent > the modeset state is that our resume path is much simpler: > - We now longer restore bogus register values (which most often would > enable the backlight a bit and a few ports), causing flickering. > - We now longer call resume_force_mode to restore a mode that the > fbcon layer would overwrite right away anyway. > > Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch> > --- > drivers/gpu/drm/i915/i915_drv.c | 5 ----- > 1 file changed, 5 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c > index fe7512a..cd6697c 100644 > --- a/drivers/gpu/drm/i915/i915_drv.c > +++ b/drivers/gpu/drm/i915/i915_drv.c > @@ -549,11 +549,6 @@ static int i915_drm_thaw(struct drm_device *dev) > intel_modeset_setup_hw_state(dev); > drm_mode_config_reset(dev); > drm_irq_install(dev); > - > - /* Resume the modeset for every activated CRTC */ > - mutex_lock(&dev->mode_config.mutex); > - drm_helper_resume_force_mode(dev); > - mutex_unlock(&dev->mode_config.mutex); > } > > intel_opregion_init(dev); Wouldn't the fb layer's modeset end up being a no-op if the suspended mode was the same as the fb mode (often the case)? Or at the very least just a flip rather than a full mode set. Though we do need to deal with non-fb, non-X resumes as well. kmscon and wayland will expect to be restored at resume time even if CONFIG_VT and the fb layer aren't compiled into the kernel. -- Jesse Barnes, Intel Open Source Technology Center
