Re: [PATCH 2/3] drm/i915: consolidate swizzling control bit frobbing

[Ben Widawsky <ben@bwidawsk.net>]

On 01/31/2012 04:47 PM, Daniel Vetter wrote:
> On gen5 we also need to correctly set up swizzling in the display
> scanout engine, but only there. Consolidate this into the same
> function.
> 
> This has a small effect on ums setups - the kernel now also sets this
> bit in addition to userspace setting it. Given that this code only
> runs when userspace either can't (resume, gpu reset) or explicitly
> won't(gem_init) touch the hw this shouldn't have an adverse effect.
> 
> Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Ben Widawsky <ben@bwidawsk.net>

> ---
>  drivers/gpu/drm/i915/i915_gem.c      |    5 ++++-
>  drivers/gpu/drm/i915/intel_display.c |    6 ------
>  2 files changed, 4 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 86fffd2..27fe07a 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -3685,13 +3685,16 @@ void i915_gem_init_swizzling(struct drm_device *dev)
>  {
>  	drm_i915_private_t *dev_priv = dev->dev_private;
>  
> -	if (INTEL_INFO(dev)->gen < 6 ||
> +	if (INTEL_INFO(dev)->gen < 5 ||
>  	    dev_priv->mm.bit_6_swizzle_x == I915_BIT_6_SWIZZLE_NONE)
>  		return;
>  
>  	I915_WRITE(DISP_ARB_CTL, I915_READ(DISP_ARB_CTL) |
>  				 DISP_TILE_SURFACE_SWIZZLING);
>  
> +	if (IS_GEN5(dev))
> +		return;
> +
>  	I915_WRITE(TILECTL, I915_READ(TILECTL) | TILECTL_SWZCTL);
>  	if (IS_GEN6(dev))
>  		I915_WRITE(ARB_MODE, ARB_MODE_ENABLE(ARB_MODE_SWIZZLE_SNB));
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index fc9bc19..5ab967c 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -6029,12 +6029,6 @@ static int ironlake_crtc_mode_set(struct drm_crtc *crtc,
>  
>  	intel_wait_for_vblank(dev, pipe);
>  
> -	if (IS_GEN5(dev)) {
> -		/* enable address swizzle for tiling buffer */
> -		temp = I915_READ(DISP_ARB_CTL);
> -		I915_WRITE(DISP_ARB_CTL, temp | DISP_TILE_SURFACE_SWIZZLING);
> -	}
> -
>  	I915_WRITE(DSPCNTR(plane), dspcntr);
>  	POSTING_READ(DSPCNTR(plane));
>