From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: Can not play audio with screen off Date: Tue, 24 May 2016 21:49:03 +0200 Message-ID: <20160524194544.GA18011@amd> References: <20160515193106.GA18685@amd> <5739D7B6.7060102@ti.com> <20160516150650.GA14639@amd> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20160516150650.GA14639@amd> Sender: linux-kernel-owner@vger.kernel.org To: Nishanth Menon Cc: pali.rohar@gmail.com, sre@kernel.org, kernel list , linux-arm-kernel , linux-omap@vger.kernel.org, tony@atomide.com, khilman@kernel.org, aaro.koskinen@iki.fi, ivo.g.dimitrov.75@gmail.com, patrikbachan@gmail.com, serge@hallyn.com List-Id: linux-omap@vger.kernel.org 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. > > Ok, so far it looks like artefact of -rc0 kernel. Lets see if it > reappers... Hmm. So it happens in vanilla 4.4, too... let me see if it happens in v4.6. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html