iLiad iLiad Power Use: A discussion (or, Leave your stylus at home) - Page 2

jharker · 11-05-2008, 04:31 PM

Quote:

Originally Posted by nekokami

Yes, exactly. Even when we're just reading, the battery lasts for a much shorter period of time than the Sony or Cybook. I always thought this was because the Wacom screen was drawing power. Apparently it isn't. Is it because the CPU is always on? Does the Sony actually stop the CPU between page turns?

Yes, the Wacom has almost nothing to do with it. The real reason is that the iLiad has no suspend mode of any kind. This is due to design. The iLiad was designed to be an "always on" device, so although it uses low power when on, it can't be made to sleep and wake up. By contrast, the Sony Reader is basically designed at the hardware level to turn almost everything off whenever it's not doing something. The tradeoff is that the Sony is only good for reading. It isn't good for anything too interactive. In contrast, the iLiad provides scribbling and other things that require the iLiad to be actually on, ready to go.

With more work it might be possible to design highly customized hardware that can allow scribbling and interactive features, yet still sleep and wake nearly instantly. But that would be tricky and much more complicated than building something using standard techniques.

All of the above is my limited understanding of the hardware situation. If I'm missing anything, I would love to be enlightened!

joelypolly · 11-05-2008, 08:33 PM

I believe based on some posts on the iLiad forums that the actual CPU doesn't support deep sleep. This would be a hardware limitation of the chip itself that can't be overcome. However, I think suspend to disk or even ram should be achievable

CommanderROR · 11-06-2008, 05:06 AM

Well, I know the Sony reader can do Suspend, but my STAReBOOK can#t, and it still lasts for about a week in "Low-Power-Mode" when just idling.
So, The CPU in the Iliad draws too much power in low power mode.

If I remeber correctly, then iRex claimed that Suspend is not possible because some driver(s) had problems waking up after Suspend. I think the CPU should be capable of deep-sleep without problems.
Another Issue that was raised back in the hey-day of battery-life-discussion was the Linux Kernel that did not work so well with the CPU. An Upgrade to 2.6 was planned but never completed as far as I know.

jharker · 11-06-2008, 11:24 AM

Quote:

Originally Posted by CommanderROR

If I remeber correctly, then iRex claimed that Suspedn is not possible because some driver(s) had problems waking up after Suspend.

Yes, now that you mention it I believe I heard something like that, too...

Quote:

I think the CPU should be capable of deep-sleep without problems.
Another Issue that was raised back in the hey-day of battery-life-discussion was the Linux Kernel that did not work so well with the CPU. An Upgrade to 2.6 was planned but never completed as far as I know.

I think an upgrade to 2.6 might fix a lot of limitations.

Another issue that I really haven't looked at: What buttons are capable of "waking" the CPU from sleep? Can any button press be configured to work, or only the power switch, or do none of the hardware buttons send the right sort of signal?

Adam B. · 11-06-2008, 11:47 AM

jharker, while doing your power tests, can you test mmc vs cf power usage?

This was a big debate, and it was generally believed that the CF slot used more power than the mmc slot when a card was inserted.

jharker · 11-06-2008, 01:14 PM

I wanted to, but I don't have an appropriate CF, MMC, or SD card available at the moment.

I did test a 2GB SD card and found very little power usage, but I don't know if this was because the card was the wrong capacity (making the reader shut down? -- unlikely?), or if the actual power useage was low.

Next week I'll have access to a CF card, so I'll give that a shot and let you know.

DigiDirk · 11-06-2008, 04:40 PM

jharker,

what I understood from the Suspend-The-CPU-Discussion is that you have
to have a hardwired signal as in "soldered to pin x" to wake - any - cpu
from suspend mode. You cannot do this with software only since software
is executed by the cpu which is... sleeping...

That's what's missing in the iLiads design.

No physical button is connected to this "pin x", I'd say nothing is connected
to said pin, so it might be possible to send the cpu into sleep mode, but there
is no way to wake it up again other than to reset or power cycle.

Even the power button does not wake the cpu, it just starts the power supply.

Please correct me if I'm wrong, but I don't want the community efforts
wasted on something the - hardware - developers declared to be non-existent.

Dirk

jharker · 11-06-2008, 05:57 PM

Hey, DigiDirk!

Sorry if I gave the wrong impression earlier-- What you say is how I understand the situation, too. So it seems hopeless, like you said. However, I don't know anything about how sleep/suspend modes work, hardware-wise. I keep hoping that someone with more experience will show us that we're wrong.

CommanderROR · 11-06-2008, 06:23 PM

I don't know whether there really is a hardware flaw. It was never really explained, at least not that I know of.

M@rcel · 11-07-2008, 05:31 AM

Is someone here brave enough to ask iRex for the iLiad hardware schematics?

0rland0 · 11-13-2008, 02:53 PM

Hey guys!
First I want to say that I'm impressed and inspired by all the activity in the Iliad community. I currently don't own the device (or any device), the thing that is holding be back is the topic at hand: the power issue, and various suspend modes.

It seems to have been discussed widely about two years ago. Irex made some official statement in their forum, however scotty1024 seemed pretty sure it could be done.

The processor in the Iliad, PXA-255 is certainly capable of suspend-to-ram. I guess the question is whether the buttons and flipbar of the Iliad is connected in such a way that they may wake up the processor. The bad news is that it didn't sound like that in the above mentioned Irex post. The good news is that the Iliad definitely can wake up by itself, at least if you believe page 70 in the Users Guide for version 2.11. It states that the Iliad can connect to the iDS even if the device is turned off.

scotty1024 also mentioned a chip, UCB1300 used for various purposes.

I don't know what all this boils down to, I'm not a hardware kind of guy, but maybe Irex are willing to give some hints now that they have released the code.

Of course, the schematics would be great, but I doubt they'll agree to that, even if someone would be brave enough

zerospinboson · 11-13-2008, 04:03 PM

is the audio subsystem disabled these days (at least when you've got the sounds disabled?)?

CommanderROR · 11-13-2008, 06:19 PM

Well, the speaker is off, and I think the audio subsystem is also off.

11-05-2008, 08:33 PM	#17
joelypolly Member Posts: 22 Karma: 328 Join Date: Jul 2008 Device: iliad	I believe based on some posts on the iLiad forums that the actual CPU doesn't support deep sleep. This would be a hardware limitation of the chip itself that can't be overcome. However, I think suspend to disk or even ram should be achievable Last edited by joelypolly; 11-06-2008 at 06:04 AM.

11-06-2008, 04:40 PM	#22
DigiDirk Connoisseur Posts: 73 Karma: 156 Join Date: Dec 2006 Device: iLiad	jharker, what I understood from the Suspend-The-CPU-Discussion is that you have to have a hardwired signal as in "soldered to pin x" to wake - any - cpu from suspend mode. You cannot do this with software only since software is executed by the cpu which is... sleeping... That's what's missing in the iLiads design. No physical button is connected to this "pin x", I'd say nothing is connected to said pin, so it might be possible to send the cpu into sleep mode, but there is no way to wake it up again other than to reset or power cycle. Even the power button does not wake the cpu, it just starts the power supply. Please correct me if I'm wrong, but I don't want the community efforts wasted on something the - hardware - developers declared to be non-existent. Dirk Last edited by DigiDirk; 11-06-2008 at 04:49 PM.

11-13-2008, 02:53 PM	#26
0rland0 Junior Member Posts: 1 Karma: 10 Join Date: Nov 2008 Device: None	This has been discussed before Hey guys! First I want to say that I'm impressed and inspired by all the activity in the Iliad community. I currently don't own the device (or any device), the thing that is holding be back is the topic at hand: the power issue, and various suspend modes. It seems to have been discussed widely about two years ago. Irex made some official statement in their forum, however scotty1024 seemed pretty sure it could be done. The processor in the Iliad, PXA-255 is certainly capable of suspend-to-ram. I guess the question is whether the buttons and flipbar of the Iliad is connected in such a way that they may wake up the processor. The bad news is that it didn't sound like that in the above mentioned Irex post. The good news is that the Iliad definitely can wake up by itself, at least if you believe page 70 in the Users Guide for version 2.11. It states that the Iliad can connect to the iDS even if the device is turned off. scotty1024 also mentioned a chip, UCB1300 used for various purposes. I don't know what all this boils down to, I'm not a hardware kind of guy, but maybe Irex are willing to give some hints now that they have released the code. Of course, the schematics would be great, but I doubt they'll agree to that, even if someone would be brave enough Last edited by 0rland0; 11-13-2008 at 02:55 PM. Reason: typo

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11-06-2008, 05:06 AM	#18
CommanderROR eink fanatic Posts: 2,022 Karma: 4924 Join Date: Mar 2006 Location: Germany Device: STAReBOOK, iRex Iliad, Sony 505, Kindle 2	Well, I know the Sony reader can do Suspend, but my STAReBOOK can#t, and it still lasts for about a week in "Low-Power-Mode" when just idling. So, The CPU in the Iliad draws too much power in low power mode. If I remeber correctly, then iRex claimed that Suspend is not possible because some driver(s) had problems waking up after Suspend. I think the CPU should be capable of deep-sleep without problems. Another Issue that was raised back in the hey-day of battery-life-discussion was the Linux Kernel that did not work so well with the CPU. An Upgrade to 2.6 was planned but never completed as far as I know.

11-06-2008, 11:47 AM	#20
Adam B. Addicted to Porting Posts: 1,697 Karma: 7194 Join Date: Oct 2006 Location: Indianapolis, IN Device: iRex iLiad, Nokia 770, Samsung i760	jharker, while doing your power tests, can you test mmc vs cf power usage? This was a big debate, and it was generally believed that the CF slot used more power than the mmc slot when a card was inserted.

11-06-2008, 01:14 PM	#21
jharker Developer Posts: 345 Karma: 3473 Join Date: Apr 2007 Location: Brooklyn, NY, USA Device: iRex iLiad v1, Blackberry Tour, Kindle DX, iPad.	I wanted to, but I don't have an appropriate CF, MMC, or SD card available at the moment. I did test a 2GB SD card and found very little power usage, but I don't know if this was because the card was the wrong capacity (making the reader shut down? -- unlikely?), or if the actual power useage was low. Next week I'll have access to a CF card, so I'll give that a shot and let you know.

11-06-2008, 05:57 PM	#23
jharker Developer Posts: 345 Karma: 3473 Join Date: Apr 2007 Location: Brooklyn, NY, USA Device: iRex iLiad v1, Blackberry Tour, Kindle DX, iPad.	Hey, DigiDirk! Sorry if I gave the wrong impression earlier-- What you say is how I understand the situation, too. So it seems hopeless, like you said. However, I don't know anything about how sleep/suspend modes work, hardware-wise. I keep hoping that someone with more experience will show us that we're wrong.

11-06-2008, 06:23 PM	#24
CommanderROR eink fanatic Posts: 2,022 Karma: 4924 Join Date: Mar 2006 Location: Germany Device: STAReBOOK, iRex Iliad, Sony 505, Kindle 2	I don't know whether there really is a hardware flaw. It was never really explained, at least not that I know of.

11-07-2008, 05:31 AM	#25
M@rcel Connoisseur Posts: 50 Karma: 32 Join Date: Aug 2008 Device: Irex iLiad	Is someone here brave enough to ask iRex for the iLiad hardware schematics?

11-13-2008, 04:03 PM	#27
zerospinboson "Assume a can opener..." Posts: 755 Karma: 1942109 Join Date: Mar 2008 Location: Local Cluster Device: iLiad v2, DR1000	is the audio subsystem disabled these days (at least when you've got the sounds disabled?)?

11-13-2008, 06:19 PM	#28
CommanderROR eink fanatic Posts: 2,022 Karma: 4924 Join Date: Mar 2006 Location: Germany Device: STAReBOOK, iRex Iliad, Sony 505, Kindle 2	Well, the speaker is off, and I think the audio subsystem is also off.

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