On Sun, Sep 29, 2019 at 01:16:20PM +0200, Arnd Bergmann wrote: > On a semi-related note, Thierry asked about one aspect of the dma-ranges > property recently, which is the behavior of dma_set_mask() and related > functions when a driver sets a mask that is larger than the memory > area in the bus-ranges but smaller than the available physical RAM. > As I understood Thierry's problem and the current code, the generic > dma_set_mask() will either reject the new mask entirely or override > the mask set by of_dma_configure, but it fails to set a correct mask > within the limitations of the parent bus in this case. There days dma_set_mask will only reject a mask if it is too small to be supported by the hardware. Larger than required masks are now always accepted.