[Letux-kernel] [Lenny400] JZ4730/Minibook framebuffer driver updates

H. Nikolaus Schaller hns at goldelico.com
Sun Sep 10 18:50:29 CEST 2017

Hi Paul,

> Am 09.09.2017 um 23:49 schrieb Paul Boddie <paul at boddie.org.uk>:
> On Saturday 9. September 2017 22.21.44 H. Nikolaus Schaller wrote:
>>> Am 09.09.2017 um 01:24 schrieb Paul Boddie <paul at boddie.org.uk>:
>>> And so, I took some clues from another place:
>>> drivers/video/fbdev/omap2/omapfb/displays/panel-dpi.c
>> Yes, this is more or less a basic decision if we want to use drm or fbdev.
>> For OMAP we had to switch X11 to omapdrm because fbdev support by X11
>> became flaky.
>> Anyways it is something that can certainly be converted later. It is even
>> possible to support both in the same kernel tree. Giving some code
>> duplication.
>> OMAP still can support fbdev but is less tested.
> Fortunately, I was only looking for inspiration here. I haven't really looked 
> at what that code does: it just happened to show me what I might be doing to 
> get the device tree structure I wanted.
> [...]
>> Applied fine. I just had a minor issue with merging things together, but
>> have solved as well.
>> Here:
>> http://git.goldelico.com/?p=gta04-kernel.git;a=heads
> I'm still figuring out my workflow, but I aim to only send patches that apply 
> to your branches.
>>> I hope these are steps in the right direction!
>> Testing will finally show but IMHO the direction is ok :)
> Well, I already found something wrong with that code: the framebuffer 
> structures use picoseconds to measure the pixel clock whereas other structures 
> use hertz or kilohertz. Attached is a patch to fix that.

Fine! I haven't applied yet but there is 4.13.1 soon so I will do and provide
a complete build asap.

BTW: I have fixed the new makesd script so that it can create SD cards that should
boot on the L400.

One is by

	DEV=/dev/sdb ./makesd lenny400

This takes the last published 2.6.24 kernel and Debian Lenny OS image where I think
that it was tested and did work. I.e. it should do the same as the ancient makesd
script found here:


The other one is

	DEV=/dev/sdb ./makesd letux-400

which takes the same Lenny OS image but installs the latest compiled mipsbook kernel
plus modules.

Both commands create SD cards that look good when mounting and inspecting elsewhere...

The only thing I don't know is if the jz4730 can handle big SD cards. I.e. bigger than
2 GB?

But in any caseI have some still working low-capacity SD cards... The smallest one
with 128 MB :)

So we are close to be able to set up a test scenario.

BR and thanks,

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