On Tue, Nov 03, 2015 at 01:25:09PM -0800, Kevin Hilman wrote: > >>>>> /* Enable clock before accessing register */ > >>>>> - ret = tegra_dma_runtime_resume(dev); > >>>>> + ret = pm_runtime_get_sync(dev); > >>>> > >>>> If you are runtime suspended then core will runtime resume you before > >>>> invoking suspend, so why do we need this > >>> > >>> Is this change now in the mainline? Do you have commit ID for that? > >>> > >>> I recall the last time we discussed this that Rafael said that they were > >>> going to do that, but he said as a rule of thumb if you need to resume > >>> it, resume it [0]. > >> > >> IIRC this has been always the behaviour, at least I see this when I test the > >> devices > > > > I have been doing some testing today and if the DMA is runtime > > suspended, then I don't see it runtime resumed before suspend is called. > > > > Can you elborate on "at least I see this when I test the devices"? What > > are you looking at? Are you using kernel function tracers in some way? > > The PM core does a _get_noresume()[1] which tries to prevent runtime > suspends *during* a system suspend. However, the PM core should not be > doing an actual runtime resume of the device, so if the device is > already runtime suspended, it will not be runtime resumed by the core, > so if the driver needs it to be runtime resumed, it needs to do it > itself. + Rafael This is contrariry to what I see, If my driver is runtime suspended and on suspend, it gets runtime resumed and then suspended -- ~Vinod -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
