Re: [PATCH 09/21] riscv: dma-mapping: skip invalidation before bidirectional DMA

2023-05-06 Thread Guo Ren
On Fri, May 5, 2023 at 9:19 PM Arnd Bergmann wrote: > > On Fri, May 5, 2023, at 07:47, Guo Ren wrote: > > On Mon, Mar 27, 2023 at 8:15 PM Arnd Bergmann wrote: > > >> > >> riscv also invalidates the caches before the transfer, which does > >> not appear to serve any purpose. > > Yes, we can't guar

Re: [PATCH 09/21] riscv: dma-mapping: skip invalidation before bidirectional DMA

2023-05-06 Thread Arnd Bergmann
On Sat, May 6, 2023, at 09:25, Guo Ren wrote: > On Fri, May 5, 2023 at 9:19 PM Arnd Bergmann wrote: >> >> This is something we can consider. Unfortunately, this is something >> that no architecture (except pa-risc, which has other problems) >> does at the moment, so we'd probably need to have a pr