[Intel-gfx] [PATCH] drm/i915: kick any firmware framebuffers before claiming the gtt

[Ville Syrjälä]

On Mon, Jun 11, 2012 at 05:07:03PM +0200, Daniel Vetter wrote:
> Especially vesafb likes to map everything as uc- (yikes), and if that
> mapping hangs around still while we try to map the gtt as wc the
> kernel will downgrade our request to uc-, resulting in abyssal
> performance.
> 
> Unfortunately we can't do this as early as readon does (i.e. as the
> first thing we do when initializing the hw) because our fb/mmio space
> region moves around on a per-gen basis. So I've had to move it below
> the gtt initialization, but that seems to work, too. The important
> thing is that we do this before we set up the gtt wc mapping.
> 
> Now an altogether different question is why people compile their
> kernels with vesafb enabled, but I guess making things just work isn't
> bad per se ...
> 
> Reported-and-tested-by: "Kilarski, Bernard R" <bernard.r.kilarski at intel.com>
> Signed-Off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> ---
>  drivers/gpu/drm/i915/i915_dma.c |   35 ++++++++++++++++++++++++++++-------
>  1 file changed, 28 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
> index 262a74d..6be01c8 100644
> --- a/drivers/gpu/drm/i915/i915_dma.c
> +++ b/drivers/gpu/drm/i915/i915_dma.c
> @@ -1401,6 +1401,25 @@ i915_mtrr_setup(struct drm_i915_private *dev_priv, unsigned long base,
>  	}
>  }
>  
> +static void i915_kick_out_firmware_fb(struct drm_i915_private *dev_priv)
> +{
> +	struct apertures_struct *ap;
> +	struct pci_dev *pdev = dev_priv->dev->pdev;
> +	bool primary = false;
> +
> +	ap = alloc_apertures(1);
> +	ap->ranges[0].base = dev_priv->dev->agp->base;
> +	ap->ranges[0].size =
> +		dev_priv->mm.gtt->gtt_mappable_entries << PAGE_SHIFT;
> +
> +#ifdef CONFIG_X86
> +	primary = pdev->resource[PCI_ROM_RESOURCE].flags & IORESOURCE_ROM_SHADOW;
> +#endif
> +
> +	remove_conflicting_framebuffers(ap, "radeondrmfb", primary);
                                             ^^^^^^^^^^^

Nice disguise :)

> +	kfree(ap);
> +}
> +
>  /**
>   * i915_driver_load - setup chip and create an initial config
>   * @dev: DRM device

-- 
Ville Syrjälä
Intel OTC