Re: [PATCH 2/4] drm/i915: Restore the display config after a GPU reset on gen4

[Daniel Vetter <daniel@ffwll.ch>]

On Mon, May 19, 2014 at 10:25:19PM +0300, ville.syrjala@linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> On pre-ctg GPU reset also resets the display hardware. Force a mode
> restore after the GPU reset, and also re-init clock gating.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index b948c71..2ec3796 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -794,6 +794,14 @@ int i915_reset(struct drm_device *dev)
>  		if (INTEL_INFO(dev)->gen > 5)
>  			intel_reset_gt_powersave(dev);
>  
> +		if (IS_GEN4(dev) && !IS_G4X(dev)) {
> +			intel_init_clock_gating(dev);
> +
> +			drm_modeset_lock_all(dev);
> +			intel_modeset_setup_hw_state(dev, true);
> +			drm_modeset_unlock_all(dev);

Locking inversion here. I think we need to push this down to the very end.
Also this leaves the interesting question of what happens with vblank
waits and friends ...
-Daniel

> +		}
> +
>  		intel_hpd_init(dev);
>  	} else {
>  		mutex_unlock(&dev->struct_mutex);
> -- 
> 1.8.5.5
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch