2013/4/22 Tomasz Figa <t.f...@samsung.com> > On Monday 22 of April 2013 12:17:39 Sylwester Nawrocki wrote: > > On 04/22/2013 12:03 PM, Inki Dae wrote: > > > > Also looks good to me. But what if power domain was disabled > without > > > > pm > > > > runtime? In this case, you must enable the power domain at > machine > > > > code or > > > > bootloader somewhere. This way would not only need some hard > codes > > > > to turn > > > > the power domain on but also not manage power management fully. > This > > > > is same as only the use of pm runtime interface(needing some hard > > > > codes without pm runtime) so I don't prefer to add > > > > clk_enable/disable to fimd probe(). I quite tend to force only > the > > > > use of pm runtime as possible. So please add the hard codes to > > > > machine code or bootloader like you did for power domain if you > > > > want to use drm fimd without pm runtime. > > > > > > That's not how the runtime PM, clock subsystems work: > > > > > > 1) When CONFIG_PM_RUNTIME is disabled, all the used hardware must > be > > > kept > > > powered on all the time. > > > > > > 2) Common Clock Framework will always gate all clocks that have > zero > > > enable_count. Note that CCF support for Exynos is already merged > for > > > 3.10 and it will be the only available clock support method for > > > Exynos. > > > > > > AFAIK, drivers must work correctly in both cases, with > > > CONFIG_PM_RUNTIME > > > enabled and disabled. > > > > > > Then is the driver worked correctly if the power domain to this device > was > > > disabled at bootloader without CONFIG_PM_RUNTIME and with > clk_enable()? I > > > think, in this case, the device wouldn't be worked correctly because > the > > > power of the device remains off. So you must enable the power domain > > > somewhere. What is the difference between these two cases? > > > > How about making the driver dependant on PM_RUNTIME and making it always > > use pm_runtime_* API, regardless if the platform actually implements > runtime > > PM or not ? Is there any issue in using the Runtime PM core always, > rather > > than coding any workarounds in drivers when PM_RUNTIME is disabled ? > > I don't think this is a good idea. This would mean that any user that from > some reasons don't want to use PM_RUNTIME, would not be able to use the > driver > anymore. > > Again. There is any case that the driver isn't worked correctly without CONFIG_PM_RUNTIME and with clk_enable(). Could you guarantee the driver to be worked correctly only adding clk_enable() to probe() without CONFIG_PM_RUNTIME? as I said before, what if the power domain to the device was disabled?
> Rafael, Kevin, do you have any opinion on this? > > Best regards, > -- > Tomasz Figa > Samsung Poland R&D Center > SW Solution Development, Kernel and System Framework > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/dri-devel >
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