On 23-10-19, 08:31, Tony Lindgren wrote: > Yegor Yefremov <yegorsli...@googlemail.com> reported that musb and ftdi > uart can fail for the first open of the uart unless connected using > a hub. > > This is because the first dma call done by musb_ep_program() must wait > if cppi41 is PM runtime suspended. Otherwise musb_ep_program() continues > with other non-dma packets before the DMA transfer is started causing at > least ftdi uarts to fail to receive data. > > Let's fix the issue by waking up cppi41 with PM runtime calls added to > cppi41_dma_prep_slave_sg() and return NULL if still idled. This way we > have musb_ep_program() continue with PIO until cppi41 is awake.
Applied and tagged stable, thanks -- ~Vinod
