Dreaming of usbnet

GregorRichards · 04-27-2010, 05:18 PM

I've been trying to hack at the DR800SG to get usbnet working, so I could debug my software on a real device with stdout/stderr actually visible ... the emulator is awesome and I use it quite a bit, but it doesn't emulate the timing perfectly (or even close), it would be nice to be able to do the same level of debugging on the device itself. To that end, I compiled g_ether.ko, put it on the device, loaded it, and it worked ...

... well, it worked until sysd decided to kill it. I believe sysd to be the culprit because when I kill sysd before starting usbnet, everything works (modulo NetworkManager's own interference). Well, everything works except for sysd, which is to say that none of the normal software works, but I can ssh in and poke around the filesystem. This is good fun, but my goal was to develop software, not to poke around the filesystem, and developing software for the iRex without sysd running is pretty much impossible.

I looked a bit through the source of sysd, but got overwhelmed very quickly ... somehow, shortly after a gadget driver is loaded, it managed to signal the USB subsytem to disconnect guest mode entirely, so the host detects a disconnect, but the device is still running the g_ether driver and has a usb network (not connected to anything). I'm hoping that somebody with a bit more experience can point me in the right direction with regards to fooling sysd into not killing my network. I'd rather not change sysd, if possible.

PS: I am not trying to do this to tether the iRex. As evidence of this I will simply say that tethering was not difficult, and not something I'm going to actually use or tell you (for any value of "you") how to do, as it's horribly unethical, though as always it was fun to do to prove it could be done. sysd doesn't need to be running for the 3G network connection to be maintained, so there is no conflict. My conflict is with normal client software (e.g. oh, Idonno, TechPDF

)

Shaggy · 04-27-2010, 05:46 PM

There's a really old thread somewhere on iRex's forum sort of along these lines. I don't remember if it dates back to the iLiad days or if it was from the DR1000 (definitely pre-dates DR800), but someone was asking about a similar capability.

My vague memory is that internally there is a connector that you can enable to see the terminal output. This is what iRex used for their own development. I think (this is going way back, so my memory is fuzzy) they also mentioned that if someone had a specific need and goals in mind, they would be willing to work with them to help get it working. I don't know if that offer still stands, or if a similar connector even exists in the DR800, but you could try sending a PM to Matthijs and see if he can offer any suggestions.

Shaggy · 04-27-2010, 05:56 PM

Found it. It applied to the iLiad, which is a different architecture, and was regarding porting the 2.6 kernel to the device. But, the interesting part is that they seemed to have been willing to work with a serious developer to hook them up with a serial/console enabled device (on loan) for certain projects.

I don't know if they'd still be willing to do that, or if the DR800 is even capable of it, but it can't hurt to ask.

Here's the thread I was thinking of (almost 3 years ago, no wonder it was a fuzzy memory).

http://forum.irexnet.com/viewtopic.p...er=asc&start=0

GregorRichards · 04-27-2010, 06:37 PM

I have a really awful habit of posting problems mere minutes before I find the solution :P

Turns out sysd finds when USB is connected by polling /sys/devices. By doing a mount -o bind over /sys/devices, I harmlessly disable its polling without breaking anything important. And I can just umount the binding when I'm done

Have I mentioned that I am absolutely in love with the hackability of the DR?

I'll post a runnable program of it for other would-be devs to have fun with, once I have it a bit more cemented.

GregorRichards · 04-27-2010, 06:44 PM

(Mind you, getting a real console would be cool too, but it's not my immediate concern)

rvs · 06-07-2011, 05:14 AM

For those interested: I found out that the connection is reset when the DR goes into idle mode. More specifically: when sysd calls idle.sh.

To circumvent this you can disable idle mode when using usbnet:

gconftool-2 -s /apps/er/sys/power/idle_mode FALSE -t bool

Using this instead of the "mount -o bind" over /sys/devices will give it more normal functionality while using usbnet. This setting is reset after a restart though, so doing an xserver restart will kill the connection.

04-27-2010, 05:18 PM	#1
GregorRichards Connoisseur Posts: 60 Karma: 151 Join Date: Apr 2010 Device: DR800SG	Dreaming of usbnet I've been trying to hack at the DR800SG to get usbnet working, so I could debug my software on a real device with stdout/stderr actually visible ... the emulator is awesome and I use it quite a bit, but it doesn't emulate the timing perfectly (or even close), it would be nice to be able to do the same level of debugging on the device itself. To that end, I compiled g_ether.ko, put it on the device, loaded it, and it worked ... ... well, it worked until sysd decided to kill it. I believe sysd to be the culprit because when I kill sysd before starting usbnet, everything works (modulo NetworkManager's own interference). Well, everything works except for sysd, which is to say that none of the normal software works, but I can ssh in and poke around the filesystem. This is good fun, but my goal was to develop software, not to poke around the filesystem, and developing software for the iRex without sysd running is pretty much impossible. I looked a bit through the source of sysd, but got overwhelmed very quickly ... somehow, shortly after a gadget driver is loaded, it managed to signal the USB subsytem to disconnect guest mode entirely, so the host detects a disconnect, but the device is still running the g_ether driver and has a usb network (not connected to anything). I'm hoping that somebody with a bit more experience can point me in the right direction with regards to fooling sysd into not killing my network. I'd rather not change sysd, if possible. PS: I am not trying to do this to tether the iRex. As evidence of this I will simply say that tethering was not difficult, and not something I'm going to actually use or tell you (for any value of "you") how to do, as it's horribly unethical, though as always it was fun to do to prove it could be done. sysd doesn't need to be running for the 3G network connection to be maintained, so there is no conflict. My conflict is with normal client software (e.g. oh, Idonno, TechPDF ) Last edited by GregorRichards; 04-27-2010 at 05:23 PM. Reason: Clarification

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04-27-2010, 05:46 PM	#2
Shaggy Wizard Posts: 4,293 Karma: 529619 Join Date: May 2007 Device: iRex iLiad, DR800SG	There's a really old thread somewhere on iRex's forum sort of along these lines. I don't remember if it dates back to the iLiad days or if it was from the DR1000 (definitely pre-dates DR800), but someone was asking about a similar capability. My vague memory is that internally there is a connector that you can enable to see the terminal output. This is what iRex used for their own development. I think (this is going way back, so my memory is fuzzy) they also mentioned that if someone had a specific need and goals in mind, they would be willing to work with them to help get it working. I don't know if that offer still stands, or if a similar connector even exists in the DR800, but you could try sending a PM to Matthijs and see if he can offer any suggestions.

04-27-2010, 05:56 PM	#3
Shaggy Wizard Posts: 4,293 Karma: 529619 Join Date: May 2007 Device: iRex iLiad, DR800SG	Found it. It applied to the iLiad, which is a different architecture, and was regarding porting the 2.6 kernel to the device. But, the interesting part is that they seemed to have been willing to work with a serious developer to hook them up with a serial/console enabled device (on loan) for certain projects. I don't know if they'd still be willing to do that, or if the DR800 is even capable of it, but it can't hurt to ask. Here's the thread I was thinking of (almost 3 years ago, no wonder it was a fuzzy memory). http://forum.irexnet.com/viewtopic.p...er=asc&start=0

04-27-2010, 06:37 PM	#4
GregorRichards Connoisseur Posts: 60 Karma: 151 Join Date: Apr 2010 Device: DR800SG	I have a really awful habit of posting problems mere minutes before I find the solution :P Turns out sysd finds when USB is connected by polling /sys/devices. By doing a mount -o bind over /sys/devices, I harmlessly disable its polling without breaking anything important. And I can just umount the binding when I'm done Have I mentioned that I am absolutely in love with the hackability of the DR? I'll post a runnable program of it for other would-be devs to have fun with, once I have it a bit more cemented.

04-27-2010, 06:44 PM	#5
GregorRichards Connoisseur Posts: 60 Karma: 151 Join Date: Apr 2010 Device: DR800SG	(Mind you, getting a real console would be cool too, but it's not my immediate concern)

06-07-2011, 05:14 AM	#6
rvs Groupie Posts: 181 Karma: 364 Join Date: Oct 2009 Device: DR1000s, Hanlin V5	For those interested: I found out that the connection is reset when the DR goes into idle mode. More specifically: when sysd calls idle.sh. To circumvent this you can disable idle mode when using usbnet: gconftool-2 -s /apps/er/sys/power/idle_mode FALSE -t bool Using this instead of the "mount -o bind" over /sys/devices will give it more normal functionality while using usbnet. This setting is reset after a restart though, so doing an xserver restart will kill the connection.

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