From: Dmitry Dmitriev <dimondmm@yandex.ru>
Subject: PROBLEM: Possible problem in i915_dma_cleanup function in i915_dma.c module
Date: Thu, 04 Aug 2011 15:02:57 +0400
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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:
=9A135static int i915_dma_cleanup(struct drm_device * dev)
=9A136{
=2E......
=9A152 =9A=9A=9A=9A=9A=9A=9A/* Clear the HWS virtual address at teardow=
n */
=9A153 =9A=9A=9A=9A=9A=9A=9Aif (I915_NEED_GFX_HWS(dev))
=9A154 =9A=9A=9A=9A=9A=9A=9A=9A=9A=9A=9A=9A=9A=9A=9Ai915_free_hws(dev);
=2E......
=9A157}

2102int i915_driver_unload(struct drm_device *dev)
2103{
=2E.......
2174 =9A=9A=9A=9A=9A=9A=9A=9A=9A=9A=9A=9A=9A=9A=9Aif (!I915_NEED_GFX_HW=
S(dev))
2175 =9A=9A=9A=9A=9A=9A=9A=9A=9A=9A=9A=9A=9A=9A=9A=9A=9A=9A=9A=9A=9A=9A=
=9Ai915_free_hws(dev);
=2E.......
2190}

I.e. in one case i915_free_hws function is called when (I915_NEED_GFX_H=
WS(dev)) condition is true(i915_dma_cleanup), but in other case it call=
ed when (!I915_NEED_GFX_HWS(dev)) condition is true(in i915_driver_unlo=
ad 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 t=
hat if condition is wrong in i915_dma_cleanup function.

Thanks,
Dmitry