Hi,

Am 19.01.2018 um 22:48 schrieb Andreas Kemnade andreas@kemnade.info:

Hi Nikolaus,

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

...

Hi Andreas,

...

Am 19.01.2018 um 07:35 schrieb Andreas Kemnade andreas@kemnade.info:

Hi,

On Thu, 18 Jan 2018 15:43:11 +0100 "H. Nikolaus Schaller" hns@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 "$@"

I found a simpler "proof of bug" using the latest kernel from our downloads:

1. boot GTA04 & connect to internet 2.

root@letux:~# cd /root root@letux:~# apt-get install libpng-dev Reading package lists... Done Building dependency tree Reading state information... Done Note, selecting 'libpng12-dev' instead of 'libpng-dev' The following NEW packages will be installed: libpng12-dev 0 upgraded, 1 newly installed, 0 to remove and 1 not upgraded. Need to get 239 kB of archives. After this operation, 515 kB of additional disk space will be used. Get:1 http://ftp.us.debian.org/debian/ jessie/main libpng12-dev armhf 1.2.50-2+deb8u3 [239 kB] Fetched 239 kB in 5s (42.0 kB/s) Selecting previously unselected package libpng12-dev:armhf. (Reading database ... 21547 files and directories currently installed.) Preparing to unpack .../libpng12-dev_1.2.50-2+deb8u3_armhf.deb ... Unpacking libpng12-dev:armhf (1.2.50-2+deb8u3) ... Processing triggers for man-db (2.7.0.2-5) ... Setting up libpng12-dev:armhf (1.2.50-2+deb8u3) ... root@letux:~# cc fbpng.c -lpng -o fbpng root@letux:~# ./fbpng /usr/share/pixmaps/debian-logo.png /usr/share/pixmaps/debian-logo.png: 48x48 @ 24bp[ 146.310180] Unhandled fault: imprecise external abort (0x1c06) at 0xb6c8d020 [ 146.321441] pgd = e15e8173 [ 146.324279] [b6c8d020] *pgd=958d2831, *pte=9e900353, *ppte=9e900873 p [ 146.331054] Unhandled fault: imprecise external abort (0x1c06) at 0xdc91bfe8 [ 146.338592] pgd = 4405b38c [ 146.341430] [dc91bfe8] *pgd=9c80041e(bad) Bus error root@letux:~#

On omap5 the same procedure succeeds.

Now I can help to find out what the reason could be...

BR, Nikolaus