Hi, I am newbee to this mailing list. Please excuse me if I am talking nonsense here. On Thu, Jul 9, 2009 at 10:48 PM, Alan Stern<stern@xxxxxxxxxxxxxxxxxxx> wrote: >> On Thu, 9 Jul 2009, Magnus Damm wrote: >> >>> Clocks should be stopped as soon as possible without any delay. The >>> clock stopping is very cheap performance wise. Also, the clock >> stopping is done on bus level without invoking any driver callbacks. >>> Delaying the clock stopping does not make any sense to me. >> >> In that case the device driver or bus subsystem should manage the >> device's clock directly. There's no need to tie it in with the runtime >> PM framework. Simply start the clock before each I/O operation and >> stop it afterward. > It's not that easy. The clock needs to be enabled to let the hardware > device perform device specific stuff. For instance, the clock for the > LCD controller needs to be on to redraw the screen. When the driver > knows that it's done with the clock it can notify the bus using > Runtime PM. Is there any plan to look into the "Clock Framework" that was developed as part of OMAP and extending this to make it generic for all platforms? -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
