On Wed, 5 Sep 2012 21:56:08 +0200 Daniel Vetter <daniel.vetter at ffwll.ch> wrote: > On Wed, Sep 5, 2012 at 8:31 PM, Jesse Barnes <jbarnes at virtuousgeek.org> wrote: > > 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. > > I guess most of the flicker was because the register restoring > restored a bunch of crap (since the old modeset state wasn't properly > cleared before suspending). > > > 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. > > Tbh I was rather surprised that when I've noticed this little issue > here the restore still worked - until I've noticed by looking at the > logs that both the fbcon and the X server restore their modes. > > I'm not sure what exactly we should do here, since even with the > current code the concept of a controlling node isn't really defined in > the kms interface (fbcon uses a bunch of funky checks to ensure it > doesn't clobber the output state of someone else). But for now (with > fbcon pretty much being non-optional) things keep on working, and > afaict actually work a bit better overall. It's probably ok for now, but at some point we'll want some code that restores the suspend mode if fbcon isn't enabled... -- Jesse Barnes, Intel Open Source Technology Center
