From 9f82d23846146990d475f6753be733e55788d88d Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Mon, 30 Aug 2010 21:25:23 +0200 Subject: [PATCH] drm/i915: overlay on gen2 can't address above 1G So set the coherent dma mask accordingly. This dma mask is only used for physical objects, so it won't really matter allocation-wise. Now this never really surfaced because sane 32bit kernels only have 1G of lowmem. But some eager testers (distros?) still carry around the patch to adjust lowmem via a kconfig option. And the kernel seems to favour high allocations on boot-up, hence the overlay blowing up reliably. Because the patch is tiny and nicely shows how broken gen2 is it's imho worth to merge despite the fact that mucking around with the lowmem/ highmem division is (no longer) supported. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=28318 Cc: stable@kernel.org Signed-off-by: Daniel Vetter Signed-off-by: Chris Wilson --- drivers/gpu/drm/i915/i915_dma.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c index a7ec93e62f81..7796f452ed1d 100644 --- a/drivers/gpu/drm/i915/i915_dma.c +++ b/drivers/gpu/drm/i915/i915_dma.c @@ -2082,6 +2082,10 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags) goto free_priv; } + /* overlay on gen2 is broken and can't address above 1G */ + if (IS_GEN2(dev)) + dma_set_coherent_mask(&dev->pdev->dev, DMA_BIT_MASK(30)); + dev_priv->regs = ioremap(base, size); if (!dev_priv->regs) { DRM_ERROR("failed to map registers\n"); -- 2.20.1