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Shreyasdm 09-27-2008 05:41 AM
Finding mobile phones using linux OS and supporting PASR
 
Hello,
I was studying mobile power management and got feature in mobile ram called 'Partial Array Self Refresh'(PASR).
I searched for a mobile phone having linux OS supporting this feature but did not get a one.

Can anyone please tell me that is this feature supported in current linux mobile phones?

Regards,
Shreyas.

john test 09-28-2008 02:27 PM
Did a quick search on "linux phone" and found the "linux mobile phone showcase" here
http://www.linuxdevices.com/articles/AT9423084269.html
A quick look shows Motorola, Samsung and others with "Linux Mobile"


Also did a google on the same and found a ton of stuff including the Linux Phone System Forum (LiPS) http://www.linuxdevices.com/articles/AT9423084269.html

Shreyasdm 09-29-2008 03:14 AM
Not able to find whether these support PASR
 
Hi,
Glad to see that world has not left me alone.
I found these mobiles and searched several opensource mobiles like openmoko and also studied different data sheets from manufacturers. But the problem is that no manufacturer is saying that it's product supports PASR feature of mobile DDR ram in software.
Can anyone please give some hint..?


Regards,
Shreyasdm.

john test 09-29-2008 09:23 AM
when I googled pasr I found this which indicates that PASR has not been implemented yet, Read from the fifth line starting with the words "This has not happened---"
Quote:
With companies now producing Low Power DRAM for handhelds, a new feature was developed called Partial Array Self Refresh (PASR). This feature enables the DRAM to retain state in only part of memory, thus further reducing the self-refresh power. If handheld operating systems could use this feature, they could potentially add hours of battery life. This has not happened because the PASR footprint provided cannot be easily integrated into established OS memory management schemes. The PASR power savings below assumes that the handheld device consumes a total of 4mW in sleep mode with the entire DRAM self-refreshed.

Shreyasdm 09-30-2008 08:53 AM
But what after 2007?
 
Hi,
Thanks John for efforts taken in this thread.
I found the original document from which John has taken the quote. It was an Intel project for Handheld devices.
This document is published in 2007. Do someone know that after 2007, any efforts taken in this direction?
By the way, assuming that no efforts are done in this direction or the efforts taken are failed, I am thinking of doing this project. But, the project requires one open source mobile handset e.g. openmoko, android that is currently not available to me ( and also costlier !!) and if emulator is used, then we cannot estimate the actual power saving.
Is there any other way round...?

Regards,
Shreyasdm.

et05hk6 09-07-2009 06:14 AM
Has anyone made any progress on this topic?


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