[Intel-gfx] [PATCH] drm/i915: Attempt to recover from page table errors.

[Zhenyu Wang]

On 2008.12.11 19:59:12 -0800, Eric Anholt wrote:
> +static int
> +i915_reset_render_and_ring(struct drm_device *dev)
> +{
> +	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
> +	int ret, i;
> +	u8 gdrst;
> +
> +	/* XXX: need more locking */
> +
> +	/* We need GEM control if we're to do this recovery.  Otherwise, the
> +	 * X Server has its own idea of what the ring state is.
> +	 */
> +	if (dev_priv->ring.ring_obj == NULL) {
> +		DRM_ERROR("Can't reset the device in non-GEM mode\n");
> +		return -EINVAL;
> +	}
> +
> +	/* Only one we've done reset for so far. */
> +	if (!IS_I965G(dev)) {
> +		DRM_ERROR("Can't reset non-G965-class devices\n");
> +		return -EINVAL;
> +	}
> +
> +	pci_read_config_byte(dev->pdev, GDRST, &gdrst);
> +	if (gdrst & GDRST_ENABLE) {
> +		DRM_ERROR("Reset started with reset bit already set!\n");
> +		return -EBUSY;
> +	}
> +
> +	pci_write_config_byte(dev->pdev, GDRST, GDRST_ENABLE | GDRST_RENDER);
> +
> +	for (i = 0; i < 100000; i++) {
> +		pci_read_config_byte(dev->pdev, GDRST, &gdrst);
> +		if ((gdrst & GDRST_ENABLE) == 0)
> +			break;
> +	}
> +	if (i == 1000000)
> +		DRM_ERROR("Failed to reset the render engine\n");

Last time I played with graphics reset bit, I used script like:

    setpci -s 00:02.0 c0.b=0x1
    sleep 1 # this should wait for reset to be effect
    setpci -s 00:02.0 c0.b=0x0
    vbetool post

I think setting reset enable bit back to 0 might be the trick here,
otherwise post didn't seem to work at all.

Really nice to see we can finally reach a reset solution with
gem & kms landing. ;)