[Solved]Kernel and Displaylink Monitor (Mimo 720f)

[pepedog]

I have been trying to get my Mimo 720f monitor to work with my RaspberryPi. A few weeks back, I recompiled the 3.6.11-7 sources and added udlfb support. I was able to get both the Displaylink monitor recognized as /dev/fb1, and the touchscreen to be recognized. It worked nicely for a few days. Unfortunately, it seems as though a firmware update (see https://github.com/raspberrypi/firmware/issues/141#issuecomment-13497434) intending to support udlfb may have upset the applecart. I can't be certain because I walked away from my project for a few weeks, and now it seems as though my custom kernel and the new stock 3.6.11-7 both don't support udlfb.

Does anyone have any insight that might help? Also, I understand that -- at least for those on Raspian -- the 3.7 series kernels support udlfb. Is there any chance of a kernel bump for RasperryPi Arch?

Thanks.

George

[pepedog]

George,
is any extra config required to be added?

[ggalt]

If you mean to the kernel configuration, I believe that you only need to select those few items in the configuration to support both the udlfb and the touchscreen for the mimo 720. I followed the directions here: http://anup.info/blog/2012/10/13/raspberry-pi-mimo-monitor and succeeded with the 3.6.11-7+ kernel source -- prior the the firmware updates mentioned before. I'm intending to rebuild the kernel under the new firmware this weekend to see if there are any issues that crop up, or if I have any success. I haven't set up a cross-compile environment, so I'm building the kernel on the Pi, which takes about 12 hours.

If you are referring to some other configuration, let me know and I'll see what I can do about getting you the information. BTW, if you want my kernel configuration that I used before, I can upload that tonight (EST-US).

George

[pepedog]

I looked thru the github thread
If you give me a list to add (eg CONFIG_INPUT_TOUCHSCREEN=y) I will get it rebuilt with latest firmware
Won't patch anything like that as I see comments like other frame buffers might be adversly affected

Edit, I will add it, think I can figure out

[pepedog]

ok, in queue to be built, both kernel and firmware

[ggalt]

@pepedog, I believe the menu commands configuring the kernel are:
1) for the Displaylink Framebuffer support:
Device Drivers -->
Graphics support -->
Support for frame buffer devices -->
*/M Displaylink USB Framebuffer support

2) for the USB touchscreen (which is hard to find through the menu):
Device Drivers -->
Input device support -->
* Touchscreens --> (NOTE, YOU MUST CHECK IT TO SEE SCREENS ON THE NEXT MENU)
M USB Touchscreen Driver (NEW)

The last will include a bunch of show a bunch of touchscreens all of which will be checked, the MIMO 720f needs the "e2i Touchscreen controller (e.g. Mimo 740)" to be check.

The config file shows the following for the touchscreens:
CONFIG_TOUCHSCREEN_USB_COMPOSITE=m
CONFIG_TOUCHSCREEN_USB_EGALAX=y
CONFIG_TOUCHSCREEN_USB_PANJIT=y
CONFIG_TOUCHSCREEN_USB_3M=y
CONFIG_TOUCHSCREEN_USB_ITM=y
CONFIG_TOUCHSCREEN_USB_ETURBO=y
CONFIG_TOUCHSCREEN_USB_GUNZE=y
CONFIG_TOUCHSCREEN_USB_DMC_TSC10=y
CONFIG_TOUCHSCREEN_USB_IRTOUCH=y
CONFIG_TOUCHSCREEN_USB_IDEALTEK=y
CONFIG_TOUCHSCREEN_USB_GENERAL_TOUCH=y
CONFIG_TOUCHSCREEN_USB_GOTOP=y
CONFIG_TOUCHSCREEN_USB_JASTEC=y
CONFIG_TOUCHSCREEN_USB_ELO=y
CONFIG_TOUCHSCREEN_USB_E2I=y
CONFIG_TOUCHSCREEN_USB_ZYTRONIC=y
CONFIG_TOUCHSCREEN_USB_ETT_TC45USB=y
CONFIG_TOUCHSCREEN_USB_NEXIO=y
CONFIG_TOUCHSCREEN_USB_EASYTOUCH=y

The important on is: "CONFIG_TOUCHSCREEN_USB_E2I=y"

For the displaylink frame buffer, the config file shows:
CONFIG_FB_UDL=y (note: could also be CONFIG_FB_UDL=m)

I've put a full copy of my config here: https://github.com/ggalt/RaspberryArch/ ... een_config

I've rebuilt my own kernel and it seems to be working. Unfortunately, I built it on the 3.6.11-6-ARCH+ sources. If you would like me to rebuild on a more recent source, let me know. Or if you would like me to test a kernel you prepare, I'm happy to do that as well.

George

[pepedog]

I did this already
https://github.com/archlinuxarm/PKGBUILDs/commit/8d652a071960882cce7fe7309858abeec0b9d7d5
It's in the queue along with firmware rebuild

[ggalt]

@pepedog: our posts must have crossed. Thanks for building the new kernel!! I'll try it out as soon as it's available.

George

[pepedog]

I appreciate you did the research George.
If you set up a github account, clone edit and push, these things (including pehaps special patches) can get into the system real quick.
Don't forget to let us know if it works. I occasionally compare the raspbian config to ours to make sure nothing left out

[ggalt]

@pepedog: OK, I've downloaded the new kernel and firmware and I can confirm that both udlfb and the touchscreen load and work. My only problem now is that the Y-axis of the touchscreen is reversed, but that isn't a kernel issue and I can hunt for a solution to that elsewhere. If anyone else is curious, the github issue thread mentioned above has my xorg config file for the displaylink driver.

Thanks for the suggestion on the github repository, I'll get to work on that. I'm afraid I'm not particularly skilled at these things, I usually get a result simply because I keep banging my head against the problem. But I'll certainly let you know if I come across anything that might be helpful.

Thanks also for all of your hard work on getting Arch running on the Raspberry Pi. These little computers are great, and having Arch running on them make them the perfect environment for experimenting. You probably don't hear it often enough, but those of us who rely on your hard work really do appreciate your efforts. If I ever get the chance, I'd like to buy you a beer (or 10).

George