[Intel-gfx] [PATCH 3/3] drm/i915/gen9: WM memory bandwidth related workaround

[kbuild test robot]

Hi Mahesh,

[auto build test WARNING on drm-intel/for-linux-next]
[also build test WARNING on next-20170130]
[cannot apply to v4.10-rc6]
[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/Mahesh-Kumar/Enable-IPC-WM-related-WA-s/20170131-230708
base:   git://anongit.freedesktop.org/drm-intel for-linux-next
config: i386-allmodconfig (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All warnings (new ones prefixed by >>):

   In file included from arch/x86/include/asm/string.h:2:0,
                    from include/linux/string.h:18,
                    from arch/x86/include/asm/page_32.h:34,
                    from arch/x86/include/asm/page.h:13,
                    from arch/x86/include/asm/processor.h:17,
                    from include/linux/mutex.h:19,
                    from include/linux/notifier.h:13,
                    from include/linux/clk.h:17,
                    from include/linux/cpufreq.h:14,
                    from drivers/gpu/drm/i915/intel_pm.c:28:
   drivers/gpu/drm/i915/intel_pm.c: In function 'skl_compute_memory_bandwidth_wm_wa':
>> drivers/gpu/drm/i915/intel_pm.c:4118:56: warning: argument to 'sizeof' in '__builtin_memcpy' call is the same expression as the destination; did you mean to dereference it? [-Wsizeof-pointer-memaccess]
     memcpy(mem_attr, &dev_priv->wm.skl_hw.mem_attr, sizeof(mem_attr));
                                                           ^
   arch/x86/include/asm/string_32.h:182:48: note: in definition of macro 'memcpy'
    #define memcpy(t, f, n) __builtin_memcpy(t, f, n)
                                                   ^

vim +4118 drivers/gpu/drm/i915/intel_pm.c

  4102			mem_attr->mem_wa = WATERMARK_WA_NONE;
  4103			return 0;
  4104		}
  4105	
  4106		if (!memdev_info->valid)
  4107			goto exit;
  4108	
  4109		/*
  4110		 * We hold wm_mutex lock, so any other flip can't proceed beyond WM
  4111		 * calculation step until this flip writes modified WM values.
  4112		 * So it's safe to read plane_state of other pipes without taking CRTC lock
  4113		 */
  4114		ret = drm_modeset_lock(&dev_priv->wm.wm_ww_mutex, state->acquire_ctx);
  4115		if (ret)
  4116			return ret;
  4117	
> 4118		memcpy(mem_attr, &dev_priv->wm.skl_hw.mem_attr, sizeof(mem_attr));
  4119	
  4120		for_each_crtc_in_state(state, crtc, cstate, i) {
  4121			struct drm_plane *plane;
  4122			const struct drm_plane_state *pstate;
  4123			int active_planes = 0;
  4124			uint32_t max_plane_bw_kbps = 0;
  4125	
  4126			mem_attr->pipe_y_tiled[i] = false;

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
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