Hi Wolfram, On Fri, Aug 31, 2018 at 11:44 AM Wolfram Sang <wsa@xxxxxxxxxxxxx> wrote: > > As a comment in the other thread said you should not set it multiple times, > > probably the best solution is to: > > (a) check if dev->dma_parms is already set, and if not: > > (b) allocate using plain kzalloc() (with a comment why!), > > (c) not free the memory nor reset dev->dma_parms (with a comment why!). > > Quite clumsy if done per driver, or? Yes it is. As for other DMA parameters (e.g. DMA mask), it's a property of the device and/or platform. So (in theory) it should be set up that way... > If this is the intended behaviour, then there is something to improve > with the dma_params API, or? If something which is meant to have a > lifecycle same as the device but needs to get set during probe/remove > lifecycle, this calls for at least a helper function which hides all > these details? Promote drivers/gpu/drm/exynos/exynos_drm_iommu.c:configure_dma_max_seg_size() to a generic helper? Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds