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Hi, all!
I need a program/driver which could change USB voltage on the fly. I need that due to iPad 2 which says "Not charging" when I connect it to my PC. I googled and find out that iPad requires higher current in USB port than most motherboards provide.
In this thread a tool for ASUS motherboards was offered but it's for Windows only. The fact that such a tool exists makes me thinking that it could be implemented for Linux too.
Thanks.
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Well for one, voltage =/= current. You're looking for a tool that changes the current that your motherboard is putting out.
Second, if you do find one, it could well damage your motherboard. The motherboard manufacturer limits the current for a reason, and Apple never intended for the iPad to be able to charge from a computer.
FYI, here are some numbers:
0.5 amps - the max current a typical USB port puts out
1.0 amps - the minimum current an iPad needs to slow charge.
2.0 amps - the minimum current an iPad needs to do its normal charge (ie same speed as the included wall adapter)
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... it could well damage your motherboard.
Emphasis on could. Obviously it depends on your specific motherboard and how it was designed.
redden0t8 wrote:The motherboard manufacturer limits the current for a reason
Then why such a software is available on the official ASUS site?
Well then that's not a case of the manufacturer limiting the current. They specifically built their motherboards to handle the extra current.
Does Gigabyte have a similar feature?
EDIT - Yes they do: http://www.gigabyte.com/microsite/185/on-off-charge.htm
Are you using the right port? At first glance it looks like the driver is only required for the on/off charge feature, the 3X charge hopefully will work without it.
Last edited by redden0t8 (2011-04-01 12:58:50)
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That's too bad, sorry to hear.
Also, sorry if I was a little negative at first, my first reaction was that I was afraid you'd find a tool that let you disable built-in safeguards. Obviously I didn't want to see you burning anything out!
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Never mind, it's ok.
Actually, I accidentally told you wrong information. When I decided to find out exact motherboard model, I realized my motherboard is ASUS P5PL2. Sorry, I had to check that far before starting the thread.
However, I have kind of good news. Here (http://ubuntuforums.org/showthread.php?t=1504845) someone solved the problem on Ubuntu 10.10 x64 and offered a small program which enables iPad charging on PC. For those who might read this thread later I provide direct links to it:
Page with the program
Direct link to zipped deb file
Direct link to source code
Unfortunately, when I connect my iPad and start the program, it says:
[bz@bolt ipad_charge]$ sudo ./ipad_charge
ipad_charge: no such device or an error occuredI'm not sure, but I guess this might be related to the problem I mentioned two days ago.
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Perhaps you can try tying two or three usb port sources together and provide greater current to your Ipad. Each port provides 500 milliamperes since that is the industry standard for usb devices. Since the source is a current device, the usb ports can be connected in parallel to supply more current.
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It would be easier to buy adapter for iPad's AC. It has american plug but I need european one.
Despite the message on the iPad which assures that it's not charging, it actually is. Slowly, but it's charging.
Another direction is to get sources of iphone-set-info, debug it and find the bug/bugs. I believe buggy iphone-set-info prevents iPad from registering in the system and that's why ipad_charger isn't working.
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Using the source tarball.
For an iPad 2 you need to change the udev rules file and ipad_charge.c:
ipad_charge.c
<#define PRODUCT_IPAD 0x129a
>#define PRODUCT_IPAD 0x129f
95-ipad_charge.rules
<ENV{DEVTYPE}=="usb_device", ACTION=="add", BUS=="usb", SYSFS{idVendor}=="05ac", SYSFS{idProduct}=="129a", RUN+="/usr/bin/ipad_charge"
>ENV{DEVTYPE}=="usb_device", ACTION=="add", BUS=="usb", SYSFS{idVendor}=="05ac", SYSFS{idProduct}=="129f", RUN+="/usr/bin/ipad_charge"
For any iPad you need to change the Makefile:
< gcc -Wall -Wextra ipad_charge.c -lusb -o ipad_charge
> gcc -Wall -Wextra ipad_charge.c -lusb-1.0 -o ipad_charge
ETA: ipad_charge does not appear to change USB port charcateristics, that is I'm still seeing usb-devices (and lsusb -v) report 500mA for the port my iPad is connected to, though it does seem to perform some hand shaking, resulting in the iPad showing that it's charging.
Last edited by bpkent (2011-04-10 19:14:42)
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