Hello!

This problem is found in 3.0 kernel.

In i915_dma_cleanup function(drivers/gpu/drm/i915/i915_dma.c module) I found following:  135static int i915_dma_cleanup(struct drm_device * dev)  136{ .......  152        /* Clear the HWS virtual address at teardown */  153        if (I915_NEED_GFX_HWS(dev))  154                i915_free_hws(dev); .......  157}

2102int i915_driver_unload(struct drm_device *dev) 2103{ ........ 2174                if (!I915_NEED_GFX_HWS(dev)) 2175                        i915_free_hws(dev); ........ 2190}

I.e. in one case i915_free_hws function is called when (I915_NEED_GFX_HWS(dev)) condition is true(i915_dma_cleanup), but in other case it called when (!I915_NEED_GFX_HWS(dev)) condition is true(in i915_driver_unload function). This is intentional?

Corresponding init function is called only when (!I915_NEED_GFX_HWS(dev)) condition is true(in i915_driver_load function). Therefore I guess that if condition is wrong in i915_dma_cleanup function.

Thanks, Dmitry