[Intel-gfx] [PATCH 05/10] [v2] drm/i915: Don't initialize watermark stuff with PCH_NOP

[Daniel Vetter]

On Wed, Mar 13, 2013 at 02:06:12PM -0700, Ben Widawsky wrote:
> v2: Move check to the top (Chris)
> Add BUG_ON for !ivybridge, since it's all we support for now (Ben)
> 
> Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
> ---
>  drivers/gpu/drm/i915/intel_pm.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 52203fd..8e7908b 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -4153,7 +4153,12 @@ void intel_init_pm(struct drm_device *dev)
>  		i915_ironlake_get_mem_freq(dev);
>  
>  	/* For FIFO watermark updates */
> -	if (HAS_PCH_SPLIT(dev)) {
> +	if (HAS_PCH_NOP(dev)) {
> +		BUG_ON(!IS_IVYBRIDGE(dev));
> +		dev_priv->display.init_clock_gating = ivybridge_init_clock_gating;
> +		dev_priv->display.update_wm = NULL;
> +		dev_priv->display.update_sprite_wm = NULL;
> +	} else if (HAS_PCH_SPLIT(dev)) {
>  		if (IS_GEN5(dev)) {
>  			if (I915_READ(MLTR_ILK) & ILK_SRLT_MASK)
>  				dev_priv->display.update_wm = ironlake_update_wm;
> @@ -4175,7 +4180,7 @@ void intel_init_pm(struct drm_device *dev)
>  			dev_priv->display.init_clock_gating = gen6_init_clock_gating;
>  		} else if (IS_IVYBRIDGE(dev)) {
>  			/* FIXME: detect B0+ stepping and use auto training */
> -			if (SNB_READ_WM0_LATENCY()) {
> +			if (SNB_READ_WM0_LATENCY() && !HAS_PCH_NOP(dev)) {
>  				dev_priv->display.update_wm = ivybridge_update_wm;
>  				dev_priv->display.update_sprite_wm = sandybridge_update_sprite_wm;
>  			} else {

I'm confused why we need this patch here - update_wm functions should only
be called when we have a pipe. If there's any caller left I think we
should fix those up, not paper over it here.

And imo it's ok to have non-NULL vfuncs here (or anywhere else, e.g.
pageflips) as long as we don't call them. After all the num_pips/PCH_NOP
checks are here to make this as unobtrusive as possible.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch