[Intel-gfx] [PATCH 2/2] drm/i915: enable 36bit physical address for hardware status page

[ykzhao]

On Tue, 2010-01-05 at 11:25 +0800, Zhenyu Wang wrote:
> This enables possible 36bit address mask on 965G that use physical
> address for hw status page.

> Signed-off-by: Zhenyu Wang <zhenyuw at linux.intel.com>
> ---
>  drivers/char/agp/intel-agp.c    |    6 +++++-
>  drivers/gpu/drm/i915/i915_dma.c |    4 ++++
>  2 files changed, 9 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/char/agp/intel-agp.c b/drivers/char/agp/intel-agp.c
> index 30c36ac..3999a5f 100644
> --- a/drivers/char/agp/intel-agp.c
> +++ b/drivers/char/agp/intel-agp.c
> @@ -2460,10 +2460,14 @@ static int __devinit agp_intel_probe(struct pci_dev *pdev,
>  				&bridge->mode);
>  	}
>  
> -	if (bridge->driver->mask_memory == intel_i965_mask_memory)
> +	if (bridge->driver->mask_memory == intel_i965_mask_memory) {
>  		if (pci_set_dma_mask(intel_private.pcidev, DMA_BIT_MASK(36)))
>  			dev_err(&intel_private.pcidev->dev,
>  				"set gfx device dma mask 36bit failed!\n");
> +		else
> +			pci_set_consistent_dma_mask(intel_private.pcidev,
> +						    DMA_BIT_MASK(36));
> +	}
It seems that both pci_set_dma_mask/set_consistent_dma_mask will be
called when the DMA mask is set correctly.

Can we use the following format so that it is easy to understand?
   if (!pci_set_dma_mask() && !pci_set_consistent_dma_mask()) {
       success;
   } else
      failure;

Do we need to add the explicit DMA mask for using 32bit DMA mask?
   
>  
>  	pci_set_drvdata(pdev, bridge);
>  	return agp_add_bridge(bridge);
> diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
> index 02607ed..750f6c8 100644
> --- a/drivers/gpu/drm/i915/i915_dma.c
> +++ b/drivers/gpu/drm/i915/i915_dma.c
> @@ -134,6 +134,10 @@ static int i915_init_phys_hws(struct drm_device *dev)
>  
>  	memset(dev_priv->hw_status_page, 0, PAGE_SIZE);
>  
> +	if (IS_I965G(dev))
> +		dev_priv->dma_status_page |= (dev_priv->dma_status_page >> 28) &
> +					     0xf0;
> +
>  	I915_WRITE(HWS_PGA, dev_priv->dma_status_page);
>  	DRM_DEBUG_DRIVER("Enabled hardware status page\n");
>  	return 0;