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Title is the full question.

Story:

I got now one of these 3.6" TFT Screens for the Pi. Now I followed this tutorial on how to set the Pi up for the screen, which is basically a changed kernel.

Now when I type in the command "uname -r" the Kernel Version is 3.6.11 which is a bit older now. But when I use "#apt-get update && apt-get upgrade" the kernel is updated an the screen doesnt work anymore.

The questions (again):

What is the pro-con of an older kernel AND

What would I need to do to update the Kernel to a newer version which also uses the Screen?

Im using a Pi B+ with Raspbian (the Image I used is from 16/02/2015)

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Not sure about that particular screen settings, but the fbtft driver has been upstreamed into the official kernel sources... TFT screens are now supported by the rpi-update kernel. If you can figure out the correct parameters for the LCD, then you can set up the /etc/modules file to load the fbtft module without having to rely on dodgy images from LCD resellers. The /etc/modules entries will look something like - 

fbtft_device name=<devicename> rotate=0
ads7846

(replacing with the correct device for your screen.)

After that you should be able to upgrade to the rpi-update kernel without losing TFT.

sudo apt-get install rpi-update
sudo rpi-update

The touchscreen is a little harder to get running. If it's resistive, it's probably an ads7846. In that case you'll need to figure out the correct dtoverlay. that'll go in /boot/config.txt once it's sussed. It looks something like - 

dtoverlay=ads7846, penirq=22, speed=500000, swapxy=0, pmax=255, xohms=70, xmin=415, xmax=3700, ymin=250, ymax=3850

Oh and as to your other question - In my experience, there are absolutely no 'pro's to using an older kernel supplied by a hardware vendor.

You can also build your own kernel. If you do that you would copy the config of your running kernel from /proc/config.gz then reconfigure and build-> (assumes you have the kernel sources and build env. set up)

cat /proc/config.gz | gunzip > /usr/src/linux/.config
make oldconfig
make
make modules
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  • Thanks :) I will try fbtft out tomorrow. Had to work With it before With some other and smaller screens. So im taking a look at the devices it supports. AS far AS i can tell no seller wrote the driver in the item description, but just pointet to the tutorial. Because im a bit New to linux , could you tell me what the kernel image does and what the differences between the versions are?
    – Matze Strawberrymaker
    Jul 9, 2015 at 0:04
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    The kernel is the core of the linux operating system. It's what the bootloader loads into memory so the computer can boot and It includes hardware drivers and core OS stuff like memory management and scheduling (either built-in or as modules). If you're new to linux, I'd recommend against trying to build your own kernel right away. The rpi-update kernel is your best bet. It's still probably going to be challenging to figure out the display settings. (BTW - Does your LCD have a touchscreen. And if so does it work with the old kernel?)
    – alphacharlie
    Jul 9, 2015 at 14:29
  • Matze - I extracted that image and did some research on it and that particular 3.6" TFT screen is one of the only ones not yet supported. It is however in active development. (the fbtft driver supports the hardware, but the init string is having to be reverse engineered.) Keep track of this thread - github.com/notro/fbtft/issues/254 as that's where the correct config will show up first.
    – alphacharlie
    Jul 9, 2015 at 16:48
  • Have already looked at it. Gonna subscribe it now. From the mechanical building it doesnt has a touchscreen, can only spot a Flatflex cable for the main driver and backlight. Mine is the same as the OP from the issue on github. Seems like im gonna need to wait.
    – Matze Strawberrymaker
    Jul 9, 2015 at 17:10

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