[Intel-gfx] [PATCH] drm/i915: Fix init_clock_gating for resume

[Rodrigo Vivi]

On Mon, Nov 13, 2017 at 02:50:28PM +0000, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> Moving the init_clock_gating() call from intel_modeset_init_hw() to
> intel_modeset_gem_init() had an unintended effect of not applying
> some workarounds on resume. This, for example, cause some kind of
> corruption to appear at the top of my IVB Thinkpad X1 Carbon LVDS
> screen after hibernation. Fix the problem by explicitly calling
> init_clock_gating() from the resume path.
> 
> I really hope this doesn't break something else again...
> 
> Cc: stable at vger.kernel.org
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Fixes: 6ac43272768c ("drm/i915: Move init_clock_gating() back to where it was")
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 9df7b5d59a94..0023fb17899f 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -1707,6 +1707,7 @@ static int i915_drm_resume(struct drm_device *dev)
>  
>  	intel_guc_resume(dev_priv);
>  
> +	intel_init_clock_gating(dev_priv);
>  	intel_modeset_init_hw(dev);

Few questions:

Any reason why here we have it before init_hw while on finish_reset
we have it after init_hw?

Also, what about the case on modeset_init? Do we need there?
If yes, shouldn't we move the call entirely to intel-modeset_init_hw?

Also, do we still need now the call on vlv_resume_prepare?
and on i915_gem_init?

Thanks,
Rodrigo.

>  
>  	spin_lock_irq(&dev_priv->irq_lock);
> -- 
> 2.13.6
> 
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