On 07/01/2020 17:12, Dmitry Osipenko wrote: > 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? No, but at the same time, I really don't see the point in this. In fact, I think it is a step backwards. If we wanted to only enable clocks while DMA channels are active we could. So I request you drop this. Jon -- nvpublic
