[Intel-gfx] [PATCH] drm/i915: Read WM before sanitize_encoder/crtc calls

[Ville Syrjälä]

On Wed, Aug 05, 2015 at 04:46:38PM +0200, Daniel Vetter wrote:
> If we shut down the crtc we might run into WM consistency checks which
> fail because we haven't yet read out the WM state. So do that before
> we sanitized the state.
> 
> This fixes a WARNING in the ilk wm code which assumes that level 0 WM
> are always enabled in it's internal tracking. But since we start out
> with all 0 in our driver structures the relevant boolean is false when
> loading. This regression was introduced in
> 
> commit 0b2ae6d72e445b58ae39cfa6ec0b8d3f53ff7a6f
> Author: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Date:   Wed Oct 9 19:17:55 2013 +0300
> 
>     drm/i915: Add intel_pipe_wm and prepare for watermark pre-compute
> 
> which added the WARN_ON(!r->enabel).
> 
> Cc: Theodore Ts'o <tytso at mit.edu>
> Reported-by: Theodore Ts'o <tytso at mit.edu>
> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
> ---
> Re-ping for testing so that I can merge this patch and send a pull to
> Linus.
> -Daniel
> ---
>  drivers/gpu/drm/i915/intel_display.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 30e0f54ba19d..ae07fd0c395c 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -15121,6 +15121,11 @@ void intel_modeset_setup_hw_state(struct drm_device *dev,
>  
>  	intel_modeset_readout_hw_state(dev);
>  
> +	if (IS_GEN9(dev))
> +		skl_wm_get_hw_state(dev);
> +	else if (HAS_PCH_SPLIT(dev))
> +		ilk_wm_get_hw_state(dev);
> +

So why not move it into intel_modeset_readout_hw_state()? Would seem
like the logical place for it.

>  	/*
>  	 * Now that we have the config, copy it to each CRTC struct
>  	 * Note that this could go away if we move to using crtc_config
> @@ -15162,11 +15167,6 @@ void intel_modeset_setup_hw_state(struct drm_device *dev,
>  		pll->on = false;
>  	}
>  
> -	if (IS_GEN9(dev))
> -		skl_wm_get_hw_state(dev);
> -	else if (HAS_PCH_SPLIT(dev))
> -		ilk_wm_get_hw_state(dev);
> -
>  	if (force_restore) {
>  		i915_redisable_vga(dev);
>  
> -- 
> 2.5.0
> 
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-- 
Ville Syrjälä
Intel OTC