Hi Marek, I love your patch! Perhaps something to improve: [auto build test WARNING on drm-exynos/exynos-drm-next] [also build test WARNING on drm-intel/for-linux-next tegra-drm/drm/tegra/for-next v5.7-rc6 next-20200519] [cannot apply to drm/drm-next] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system. BTW, we also suggest to use '--base' option to specify the base tree in git format-patch, please see https://stackoverflow.com/a/37406982] url: https://github.com/0day-ci/linux/commits/Marek-Szyprowski/drm-exynos-Fix-dma_parms-allocation/20200521-015443 base: https://git.kernel.org/pub/scm/linux/kernel/git/daeinki/drm-exynos.git exynos-drm-next config: alpha-allyesconfig (attached as .config) compiler: alpha-linux-gcc (GCC) 9.3.0 reproduce: wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=alpha If you fix the issue, kindly add following tag as appropriate Reported-by: kbuild test robot All warnings (new ones prefixed by >>, old ones prefixed by <<): drivers/gpu/drm/exynos/exynos_drm_dma.c: In function 'drm_iommu_attach_device': >> drivers/gpu/drm/exynos/exynos_drm_dma.c:47:6: warning: variable 'ret' set but not used [-Wunused-but-set-variable] 47 | int ret; | ^~~ vim +/ret +47 drivers/gpu/drm/exynos/exynos_drm_dma.c 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 33 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 34 /* 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 35 * drm_iommu_attach_device- attach device to iommu mapping 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 36 * 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 37 * @drm_dev: DRM device 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 38 * @subdrv_dev: device to be attach 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 39 * 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 40 * This function should be called by sub drivers to attach it to iommu 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 41 * mapping. 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 42 */ 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 43 static int drm_iommu_attach_device(struct drm_device *drm_dev, 07dc3678bacc2a75 Marek Szyprowski 2020-03-09 44 struct device *subdrv_dev, void **dma_priv) 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 45 { 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 46 struct exynos_drm_private *priv = drm_dev->dev_private; 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 @47 int ret; 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 48 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 49 if (get_dma_ops(priv->dma_dev) != get_dma_ops(subdrv_dev)) { 6f83d20838c09936 Inki Dae 2019-04-15 50 DRM_DEV_ERROR(subdrv_dev, "Device %s lacks support for IOMMU\n", 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 51 dev_name(subdrv_dev)); 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 52 return -EINVAL; 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 53 } 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 54 1698f69d5f384fad Marek Szyprowski 2020-05-20 55 dma_set_max_seg_size(subdrv_dev, DMA_BIT_MASK(32)); 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 56 if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)) { 07dc3678bacc2a75 Marek Szyprowski 2020-03-09 57 /* 07dc3678bacc2a75 Marek Szyprowski 2020-03-09 58 * Keep the original DMA mapping of the sub-device and 07dc3678bacc2a75 Marek Szyprowski 2020-03-09 59 * restore it on Exynos DRM detach, otherwise the DMA 07dc3678bacc2a75 Marek Szyprowski 2020-03-09 60 * framework considers it as IOMMU-less during the next 07dc3678bacc2a75 Marek Szyprowski 2020-03-09 61 * probe (in case of deferred probe or modular build) 07dc3678bacc2a75 Marek Szyprowski 2020-03-09 62 */ 07dc3678bacc2a75 Marek Szyprowski 2020-03-09 63 *dma_priv = to_dma_iommu_mapping(subdrv_dev); 07dc3678bacc2a75 Marek Szyprowski 2020-03-09 64 if (*dma_priv) 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 65 arm_iommu_detach_device(subdrv_dev); 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 66 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 67 ret = arm_iommu_attach_device(subdrv_dev, priv->mapping); 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 68 } else if (IS_ENABLED(CONFIG_IOMMU_DMA)) { 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 69 ret = iommu_attach_device(priv->mapping, subdrv_dev); 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 70 } 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 71 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 72 return 0; 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 73 } 67fbf3a3ef84436c Andrzej Hajda 2018-10-12 74 :::::: The code at line 47 was first introduced by commit :::::: 67fbf3a3ef84436c58b5ead53b4b866125ad7ce9 drm/exynos/iommu: merge IOMMU and DMA code :::::: TO: Andrzej Hajda :::::: CC: Inki Dae --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org