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

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