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I want to use my old android tab (dead) display with Raspberry Pi. I am thinking of connecting screen via I/O ports of Raspberry Pi.

I need to find display driver for tabs screen, as my Tab is dead, I can not find its display specification & can not find manufacturer, Is there any other way so that I can move further?

Can extracting display driver from tab android OS help?

  • 1
    Well, is there no label on that tab? With vendor, type and model the "internet" should at least provide some ideas what kind of display and respective display controller this is. Be aware however that "connect to GPIO" might not be as simple as expected. Prepare for a bigger adventure in any case. – Ghanima May 4 '15 at 14:35
  • Its local one and there is not much detail about it – user1917769 May 4 '15 at 14:51
  • @Ghanima Will it not be easy one after I find display driver for screen, and Is there not any linux utility to find display driver automatically? – user1917769 May 4 '15 at 14:58
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It is not that simple. Actually, it's extremely difficult and possibly NOT even possible. The LCD it self does not use a driver, the GPU uses a driver.

OS <==DRIVER==> GPU <==HARDWARE==> DISPLAY

Take a traditional desktop. Your screens don't use an LCD driver installed on the OS.

  • You install the driver for the GPU.
  • The GPU provides screen data on a standardised link, like VGA, HDMI or DP.
  • The screen receives the data and the hardware decodes it and pushes pixels to the LCD screen.

The same applies in embedded devices like tablets, just the only thing missing, is the standardised link, because there is no point in adding more components for interfaces, since its embedded and not designed to be replaced by a bigger LCD, cause it wont fit, or to be used as a stand alone screen. The LCD is connected to the GPU in whatever way the GPU vendor finds it is best way to do it, and 90% of the time, non standard.

The operating system has a graphic layer which needs a driver to communicate with the GPU in a standard way, like DirectX but more like OpenGL. Then DirectX or OpenGL uses the driver for the GPU. The rest, is unknown to the OS.

Making things even more complicated is that GPU and CPU are usually embedded into single chip (SoC) with DMA access between these two systems. Meaning that the CPU must be running in order to communicate with the GPU, which requires more drivers, running on an OS, which requires a working tablet.

Connecting any kind of LCD directly to a Pi is practically impossible mainly because there are no specifications on what to connect where, but mostly because the GPIO is not even fast enough to deliver such data to the LCD - Since the LCD has a "driver PCB" which, is specific hardware to decode specific data for the LCD to operate. Trying to do that in software would be painful and a waste of time, since even the same tablet models, may use different versions of an LCD, produced in separate parts of the world, with a slightly modified GPU (very common in Apple device)

The Raspberry Pi has a CSI port, which is like their kind of standard way to connect an LCD directly to the GPU, but the LCD needs to support CSI (with additional hardware drivers), just like connecting a desktop screen requires and HDMI or DP cable.

--EDIT May 2019

As the Raspberry 4 is rumoured to be released with a programmable FPGA this could technically mean you could drive a LCD directly. If you knew how to convert the frame buffer, CSI, HDMI signal (unclear of what access the FPGA will have) you could emulate a driver board. If it is true then that means we will start seeing a ton of repositories that could become use full for reusing old LCD's, but not limited to just LCD's - for example.

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