Hi Matthew,

[auto build test WARNING on drm-intel/for-linux-next]
[also build test WARNING on next-20170405]
[cannot apply to v4.11-rc5]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Matthew-Auld/drm-i915-initial-support-for-huge-gtt-pages-V2/20170406-060958
base:   git://anongit.freedesktop.org/drm-intel for-linux-next
config: x86_64-randconfig-s2-04061013 (attached as .config)
compiler: gcc-4.4 (Debian 4.4.7-8) 4.4.7
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All warnings (new ones prefixed by >>):

   drivers/gpu/drm/i915/i915_gem_gtt.c: In function 'gen8_ppgtt_insert_4lvl':
>> drivers/gpu/drm/i915/i915_gem_gtt.c:1002: warning: 'iter' is used uninitialized in this function
   drivers/gpu/drm/i915/i915_gem_gtt.c: In function 'gen8_ppgtt_insert_3lvl':
   drivers/gpu/drm/i915/i915_gem_gtt.c:983: warning: 'iter.sg' is used uninitialized in this function
   drivers/gpu/drm/i915/i915_gem_gtt.c:984: warning: 'iter.dma' is used uninitialized in this function

vim +/iter +1002 drivers/gpu/drm/i915/i915_gem_gtt.c

9e89f9ee3 Chris Wilson   2017-02-25   986  	struct gen8_insert_pte idx = gen8_insert_pte(start);
de5ba8eb9 Michel Thierry 2015-08-03   987  
9e89f9ee3 Chris Wilson   2017-02-25   988  	gen8_ppgtt_insert_pte_entries(ppgtt, &ppgtt->pdp, &iter, &idx,
9e89f9ee3 Chris Wilson   2017-02-25   989  				      cache_level);
de5ba8eb9 Michel Thierry 2015-08-03   990  }
894ccebee Chris Wilson   2017-02-15   991  
894ccebee Chris Wilson   2017-02-15   992  static void gen8_ppgtt_insert_4lvl(struct i915_address_space *vm,
894ccebee Chris Wilson   2017-02-15   993  				   struct sg_table *pages,
75c7b0b86 Chris Wilson   2017-02-15   994  				   u64 start,
c7a43c911 Matthew Auld   2017-04-04   995  				   unsigned int page_size,
894ccebee Chris Wilson   2017-02-15   996  				   enum i915_cache_level cache_level,
894ccebee Chris Wilson   2017-02-15   997  				   u32 unused)
894ccebee Chris Wilson   2017-02-15   998  {
894ccebee Chris Wilson   2017-02-15   999  	struct i915_hw_ppgtt *ppgtt = i915_vm_to_ppgtt(vm);
894ccebee Chris Wilson   2017-02-15  1000  	struct sgt_dma iter = {
894ccebee Chris Wilson   2017-02-15  1001  		.sg = pages->sgl,
894ccebee Chris Wilson   2017-02-15 @1002  		.dma = sg_dma_address(iter.sg),
894ccebee Chris Wilson   2017-02-15  1003  		.max = iter.dma + iter.sg->length,
894ccebee Chris Wilson   2017-02-15  1004  	};
894ccebee Chris Wilson   2017-02-15  1005  	struct i915_page_directory_pointer **pdps = ppgtt->pml4.pdps;
9e89f9ee3 Chris Wilson   2017-02-25  1006  	struct gen8_insert_pte idx = gen8_insert_pte(start);
c7a43c911 Matthew Auld   2017-04-04  1007  	bool (*insert_entries)(struct i915_hw_ppgtt *ppgtt,
c7a43c911 Matthew Auld   2017-04-04  1008  			       struct i915_page_directory_pointer *pdp,
c7a43c911 Matthew Auld   2017-04-04  1009  			       struct sgt_dma *iter,
c7a43c911 Matthew Auld   2017-04-04  1010  			       struct gen8_insert_pte *idx,

:::::: The code at line 1002 was first introduced by commit
:::::: 894ccebee2b0e606ba9638d20dd87b33568482d7 drm/i915: Micro-optimise gen8_ppgtt_insert_entries()

:::::: TO: Chris Wilson <chris@chris-wilson.co.uk>
:::::: CC: Chris Wilson <chris@chris-wilson.co.uk>

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