[Intel-gfx] [PATCH] drm/i915: Call i915_gem_suspend() only after display is turned off

[Souza, Jose]

On Fri, 2022-06-17 at 12:28 -0700, Matt Roper wrote:
> On Fri, Jun 17, 2022 at 12:06:29PM -0700, José Roberto de Souza wrote:
> > Gem buffers could still be in use by display after i915_gem_suspend()
> > is executed so there is chances that i915_gem_flush_free_objects()
> > will be being executed at the same time that
> > intel_runtime_pm_driver_release() is executed printing warnings about
> > wakerefs will being held.
> 
> By the same logic do we need to adjust i915_driver_remove() too?

Nope, all display buffers are freed in i915_driver_unregister() call chain:


i915_driver_remove()
	i915_driver_unregister()
		intel_display_driver_unregister()
			drm_atomic_helper_shutdown()
	i915_gem_suspend()
		i915_gem_drain_freed_objects()


Only FBC compressed framebuffer is freed after that but that will not cause any warnings as it is allocated from stolen memory.

> 
> 
> Matt
> 
> > 
> > So here only calling i915_gem_suspend() and by consequence
> > i915_gem_drain_freed_objects() only after display is down making
> > sure all buffers are freed.
> > 
> > Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_driver.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_driver.c b/drivers/gpu/drm/i915/i915_driver.c
> > index d26dcca7e654a..4227675dd1cfe 100644
> > --- a/drivers/gpu/drm/i915/i915_driver.c
> > +++ b/drivers/gpu/drm/i915/i915_driver.c
> > @@ -1067,8 +1067,6 @@ void i915_driver_shutdown(struct drm_i915_private *i915)
> >  	intel_runtime_pm_disable(&i915->runtime_pm);
> >  	intel_power_domains_disable(i915);
> >  
> > -	i915_gem_suspend(i915);
> > -
> >  	if (HAS_DISPLAY(i915)) {
> >  		drm_kms_helper_poll_disable(&i915->drm);
> >  
> > @@ -1085,6 +1083,8 @@ void i915_driver_shutdown(struct drm_i915_private *i915)
> >  
> >  	intel_dmc_ucode_suspend(i915);
> >  
> > +	i915_gem_suspend(i915);
> > +
> >  	/*
> >  	 * The only requirement is to reboot with display DC states disabled,
> >  	 * for now leaving all display power wells in the INIT power domain
> > -- 
> > 2.36.1
> > 
>