On 05/15/2016 02:31 PM, Pavel Machek wrote: > Hi! > > I'm playing some more with N900, this time I'd like to use it as a > alarm clock... > > And now I realized I can not, because system performance is so > horrible with screen off that mpg123 + pulseaudio skips horribly. This > is without tweaking serial parameters, so CPU is definitely not going > into the idle/off modes. > > Loading CPU fixes the issue (I used cat /dev/zero > /dev/null). > > Hmm. And it seems to work better if I ssh in and launch mpg123 > remotely. Weird. > > Kernel 4.5-rc0. Will try on different ones. > > Any ideas? Is there interface to tell kernel that better performance > is needed for a while? > pm_qos cpu_dma_latency? Drivers will have to be properly instrumented with appropriate latency values -> this will control the depth in C states that the system will attempt. NOTE: it is a dual edged sword, bad configurations can result in none of the C-states being entered. -- Regards, Nishanth Menon -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
