Re: [PATCH 3/3] drm/virtio: use the fence for every plane update

[kernel test robot <lkp@intel.com>]

Hi Dongwon,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on drm/drm-next]
[also build test WARNING on drm-exynos/exynos-drm-next drm-intel/for-linux-next drm-tip/drm-tip tegra-drm/drm/tegra/for-next v5.18-rc6 next-20220510]
[cannot apply to airlied/drm-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/intel-lab-lkp/linux/commits/Dongwon-Kim/drm-virtio-release-ops-for-virtgpu-fence-release/20220511-081226
base:   git://anongit.freedesktop.org/drm/drm drm-next
config: arm-randconfig-r015-20220509 (https://download.01.org/0day-ci/archive/20220511/202205111533.LaZm5cYP-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 18dd123c56754edf62c7042dcf23185c3727610f)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install arm cross compiling tool for clang build
        # apt-get install binutils-arm-linux-gnueabi
        # https://github.com/intel-lab-lkp/linux/commit/5c7787de5069b504754aea17bf8137faae26fe66
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Dongwon-Kim/drm-virtio-release-ops-for-virtgpu-fence-release/20220511-081226
        git checkout 5c7787de5069b504754aea17bf8137faae26fe66
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash drivers/gpu/drm/virtio/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> drivers/gpu/drm/virtio/virtgpu_plane.c:147:6: warning: variable 'objs' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
           if (fence) {
               ^~~~~
   drivers/gpu/drm/virtio/virtgpu_plane.c:158:26: note: uninitialized use occurs here
                                         width, height, objs, fence);
                                                        ^~~~
   drivers/gpu/drm/virtio/virtgpu_plane.c:147:2: note: remove the 'if' if its condition is always true
           if (fence) {
           ^~~~~~~~~~~
   drivers/gpu/drm/virtio/virtgpu_plane.c:140:38: note: initialize the variable 'objs' to silence this warning
           struct virtio_gpu_object_array *objs;
                                               ^
                                                = NULL
   1 warning generated.


vim +147 drivers/gpu/drm/virtio/virtgpu_plane.c

544c521d4ab8f2a Gerd Hoffmann   2019-10-23  131  
5c68ab9276aae47 Vivek Kasireddy 2021-06-10  132  static void virtio_gpu_resource_flush(struct drm_plane *plane,
5c68ab9276aae47 Vivek Kasireddy 2021-06-10  133  				      uint32_t x, uint32_t y,
5c68ab9276aae47 Vivek Kasireddy 2021-06-10  134  				      uint32_t width, uint32_t height)
5c68ab9276aae47 Vivek Kasireddy 2021-06-10  135  {
5c68ab9276aae47 Vivek Kasireddy 2021-06-10  136  	struct drm_device *dev = plane->dev;
5c68ab9276aae47 Vivek Kasireddy 2021-06-10  137  	struct virtio_gpu_device *vgdev = dev->dev_private;
5c68ab9276aae47 Vivek Kasireddy 2021-06-10  138  	struct virtio_gpu_framebuffer *vgfb;
5c68ab9276aae47 Vivek Kasireddy 2021-06-10  139  	struct virtio_gpu_object *bo;
47558b189c1d340 Dongwon Kim     2022-05-10  140  	struct virtio_gpu_object_array *objs;
47558b189c1d340 Dongwon Kim     2022-05-10  141  	struct virtio_gpu_fence *fence;
5c68ab9276aae47 Vivek Kasireddy 2021-06-10  142  
5c68ab9276aae47 Vivek Kasireddy 2021-06-10  143  	vgfb = to_virtio_gpu_framebuffer(plane->state->fb);
5c68ab9276aae47 Vivek Kasireddy 2021-06-10  144  	bo = gem_to_virtio_gpu_obj(vgfb->base.obj[0]);
5c7787de5069b50 Dongwon Kim     2022-05-10  145  	fence = virtio_gpu_fence_alloc(vgdev, vgdev->fence_drv.context, 0);
47558b189c1d340 Dongwon Kim     2022-05-10  146  
47558b189c1d340 Dongwon Kim     2022-05-10 @147  	if (fence) {
5c68ab9276aae47 Vivek Kasireddy 2021-06-10  148  		objs = virtio_gpu_array_alloc(1);
47558b189c1d340 Dongwon Kim     2022-05-10  149  		if (!objs) {
47558b189c1d340 Dongwon Kim     2022-05-10  150  			kfree(fence);
5c68ab9276aae47 Vivek Kasireddy 2021-06-10  151  			return;
47558b189c1d340 Dongwon Kim     2022-05-10  152  		}
5c68ab9276aae47 Vivek Kasireddy 2021-06-10  153  		virtio_gpu_array_add_obj(objs, vgfb->base.obj[0]);
5c68ab9276aae47 Vivek Kasireddy 2021-06-10  154  		virtio_gpu_array_lock_resv(objs);
47558b189c1d340 Dongwon Kim     2022-05-10  155  	}
47558b189c1d340 Dongwon Kim     2022-05-10  156  
5c68ab9276aae47 Vivek Kasireddy 2021-06-10  157  	virtio_gpu_cmd_resource_flush(vgdev, bo->hw_res_handle, x, y,
47558b189c1d340 Dongwon Kim     2022-05-10  158  				      width, height, objs, fence);
5c68ab9276aae47 Vivek Kasireddy 2021-06-10  159  	virtio_gpu_notify(vgdev);
5c68ab9276aae47 Vivek Kasireddy 2021-06-10  160  
47558b189c1d340 Dongwon Kim     2022-05-10  161  	if (fence) {
47558b189c1d340 Dongwon Kim     2022-05-10  162  		dma_fence_wait_timeout(&fence->f, true,
5c68ab9276aae47 Vivek Kasireddy 2021-06-10  163  				       msecs_to_jiffies(50));
47558b189c1d340 Dongwon Kim     2022-05-10  164  		dma_fence_put(&fence->f);
5c68ab9276aae47 Vivek Kasireddy 2021-06-10  165  	}
5c68ab9276aae47 Vivek Kasireddy 2021-06-10  166  }
5c68ab9276aae47 Vivek Kasireddy 2021-06-10  167  

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