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Groups > linux.kernel > #1401197 > unrolled thread
| Started by | Pavel Machek <pavel@ucw.cz> |
|---|---|
| First post | 2016-05-16 04:10 +0200 |
| Last post | 2016-05-24 21:50 +0200 |
| Articles | 4 — 2 participants |
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Can not play audio with screen off Pavel Machek <pavel@ucw.cz> - 2016-05-16 04:10 +0200
Re: Can not play audio with screen off Nishanth Menon <nm@ti.com> - 2016-05-16 16:30 +0200
Re: Can not play audio with screen off Pavel Machek <pavel@ucw.cz> - 2016-05-16 17:10 +0200
Re: Can not play audio with screen off Pavel Machek <pavel@ucw.cz> - 2016-05-24 21:50 +0200
| From | Pavel Machek <pavel@ucw.cz> |
|---|---|
| Date | 2016-05-16 04:10 +0200 |
| Subject | Can not play audio with screen off |
| Message-ID | <rzg8S-u7-139@gated-at.bofh.it> |
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? Thanks, Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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| From | Nishanth Menon <nm@ti.com> |
|---|---|
| Date | 2016-05-16 16:30 +0200 |
| Message-ID | <rzrGW-892-1@gated-at.bofh.it> |
| In reply to | #1401197 |
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
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| From | Pavel Machek <pavel@ucw.cz> |
|---|---|
| Date | 2016-05-16 17:10 +0200 |
| Message-ID | <rzsjD-9W-1@gated-at.bofh.it> |
| In reply to | #1401527 |
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... Thanks, Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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| From | Pavel Machek <pavel@ucw.cz> |
|---|---|
| Date | 2016-05-24 21:50 +0200 |
| Message-ID | <rCqv0-7wp-25@gated-at.bofh.it> |
| In reply to | #1401557 |
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
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