Hello Jon, 07.01.2020 18:13, Jon Hunter пишет: > > On 06/01/2020 01:17, Dmitry Osipenko wrote: >> There is no benefit from runtime PM usage for the APB DMA driver because >> it enables clock at the time of channel's allocation and thus clock stays >> enabled all the time in practice, secondly there is benefit from manually >> disabled clock because hardware auto-gates it during idle by itself. > > This assumes that the channel is allocated during a driver > initialisation. That may not always be the case. I believe audio is one > case where channels are requested at the start of audio playback. At least serial, I2C, SPI and T20 FUSE are permanently keeping channels allocated, thus audio is an exception here. I don't think that it's practical to assume that there is a real-world use-case where audio driver is the only active DMA client. The benefits of gating the DMA clock are also dim, do you have any power-consumption numbers that show that it's really worth to care about the clock-gating?
