[Letux-kernel] [PATCH] fbpng: make it work with 32 bpp fb

[Andreas Kemnade]

Hi Nikolaus,

On Fri, 19 Jan 2018 07:45:22 +0100
"H. Nikolaus Schaller" <hns at goldelico.com> wrote:

> Hi Andreas,
> 
> > Am 19.01.2018 um 07:35 schrieb Andreas Kemnade <andreas at kemnade.info>:
> > 
> > Hi,
> > 
> > On Thu, 18 Jan 2018 15:43:11 +0100
> > "H. Nikolaus Schaller" <hns at goldelico.com> wrote:
> >   
> >> Hi Andreas,
> >> queued for inclusion.
> >> 
> >> BTW: I have tried cat /dev/urandom >/dev/fb0 and had not seen hangs or
> >> bus errors. Well, I also haven't seen anything since an X server was running.
> >> And I haven't done heavy load testing or randomized page allocation effects.
> >>   
> > I just stopped the xserver and then called fbpng. I guess the key point is to
> > mmap() the device (which seems to be usual thing you do).  
> 
> Ah, ok.
> 
> So normal read()/write() (cat >/dev/fb0) may even succeed while mmap fails?
> This explains why I could not such effects yet.
> 
> > I am preparing a test setup to be simply started by uboot-start-kernel.sh  
> 
here are the steps
download and unpack

http://misc.andi.de1.cc/fbdev-test.tar.gz

copy a modules.tgz containing the modules+modules.dep of the kernel to
test (your modules.tgz is lacking a modules.dep for whatever reason)

cd fbdev-test
./convert-mod-tgz.sh

usb-start-kernel.sh /path/to/uImage fbtest-initrd-mod.img /path/to/device.dtb root=/dev/none console=tty0

It should create a text console after some delay.
Some seconds later it should display a nearly empty battery.
With tiler patches, it just hangs.

The base initramfs is created using
mkinitramfs using the configuration files at
https://misc.andi.de1.cc/initramfs-fbtest.tar.gz
from a jessie system

It includes a compiled fbpng from the kernel letux directory.

BTW:
how do you create the modules.tgz so that it does not contain a modules.dep?
I am using this
makearmkernel modules_install INSTALL_MOD_PATH=$PWD/dst INSTALL_MOD_STRIP=1

as a base for deploying the freshly-built modules to the gta04

makearmkernel is just:
#!/bin/bash
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- CC=arm-linux-gnueabihf-gcc LOADADDR=0x80008000 "$@"

Regards,
Andreas