Often devices allocate dma buffers before they do runtime pm resume. This is the case for example with v4l2 devices where buffers are allocated during 'VIDIOC_REQBUFS` and runtime resume happens later usually during 'VIDIOC_STREAMON'. In such cases the partial tlb flush when allocating will fail since the the iommu is runtime suspended. This will print a warning and try to do full flush. But there is actually no need to flush the tlb before the consumer device is turned on. Fix the warning by skipping parital flush when allocating and instead do full flash in runtime resume This patchset is a combination of a patch already sent in a different patchset: [1] and a warning fix from Sebastian Reichel [1] https://lore.kernel.org/linux-devicetree/20210923115840.17813-13-yong.wu@xxxxxxxxxxxx/ Sebastian Reichel (1): iommu/mediatek: always check runtime PM status in tlb flush range callback Yong Wu (1): iommu/mediatek: Always tlb_flush_all when each PM resume drivers/iommu/mtk_iommu.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) -- 2.17.1
