[Dev] [Porting on Beaglebone] A stupid question about display porting.

Hee-cheol Yang heecheol.yang at outlook.com
Mon May 15 13:30:12 GMT 2017


Hello

First of all, thank you very much for all helps.
Until now, I found that the beaglebone black(BBB) Linux kernel supports DRM-HDMI well:

  1.  Running modetest via HDMI which works well.
  2.  There are /sys/class/drm/CARD0-* files.

So I currently testing libtdm and libtbm to display desktop interface on my TV. It seems that the main problem is that the backends coludn’t find DRM interfaces via udev even the kernel itself supports it, because no udev rules are desscribed in the udev configuration directories.

Unfortunately, as I know, TI doesn’t officially support any other graphic stacks except X windows system. So my current plan is to benchmark wayland based solutions which someone ported on the same board.
After that, I will try to port opengl-es stack.

Thanks very much for your help again.

Best regards.

Heecheol, Yang

보낸 사람: 박보람<mailto:boram1288.park at samsung.com>
보낸 날짜: 2017년 5월 12일 금요일 오후 5:12
받는 사람: heecheol.yang at outlook.com<mailto:heecheol.yang at outlook.com>
참조: dev at lists.tizen.org<mailto:dev at lists.tizen.org>
제목: Re: [Dev] [Porting on Beaglebone] A stupid question about display porting.


Hello



To port tizen on new device, the backend of libtdm and libtbm should be prepared. Usually, if kernel supports DRM interface, libtdm-drm and libtbm-dumb wouldn't have any problem.

So, you'd better check the kernel DRM module first with "modetest" tool.
To use it, you need to download and install libdrm-tools and libkms rpm pkgs from http://download.tizen.org/snapshots/tizen/3.0-common/latest/repos/arm-wayland/packages/armv7l/

​
Belows are simple example how to use it.



root at localhost<mailto:root at localhost>:~# modetest
...
trying to open device 'exynos'...success.
....
CRTCs:
id      fb      pos     size
20      34      (0,0)   (1920x1080)
  1920x1080 60 1920 2008 2052 2200 1080 1084 1089 1125 flags: phsync, pvsync; type: preferred, driver
  props:
.....
root at localhost<mailto:root at localhost>:~# modetest -P 20:1920x1080 at AR24           <== 20(crtc id). The image which contains many red, yellow, green lines should be displayed on screen.



If "modetest -P 20:1920x1080 at AR24" works fine, need to tdm and tbm operation with "dlogutil TDM TBM" command.



Regards
Boram

On 05/12/2017 12:40 AM, Hee-cheol Yang wrote:
>
> Hello,
>
> First of all, I am very sorry for my sound-stupid question.
>
> This quest may be out out the scope of this mailing list.
>
> If so, please ignore this mail.
>
>
>
>
>
> I am trying to port tizen 3.0-common on Beaglebone Black board, which is based on TI’s AM335x SoC.
>
> And currently, I booted the latest Tizen3.0-common rootfs(http://download.tizen.org/snapshots/tizen/3.0-common/latest/images/arm-wayland/common-wayland-3parts-armv7l-artik/) on the modified Beaglebone’s Linux kernel, which is configured to support SMACK. As you may expected, it is not working correctly, so I am trying to solve the problems step by step.
>
>
>
> My first goal is to display something in the Monitor via HDMI interfance (Beaglebone black board’s default display is the HDMI monitor). And it seems that the HDMI itself seems to working because:
>
>     /dev/fb0 is exposed.
>     Something is displayed when I run “dd if=/dev/urandom of=/dev/fb0”
>
>
>
> However, even the /dev/fb0 seems to be working, Any Tizen-relased graphics are not displayed the monitor, and after spending several days of searching, I found that TDM and TBM are need to be ported for the SOC. In this case, AM335x SOC.
>
>
>
> But As I understand, using libtdm-drm and libdbm-dummy is sufficient to show basic display components without porting any device-specific interfaces for libtdx’s interface between front and backends. Also, when I used libtdm-drm and libdbm-dummy, it seems that something recognizable graphics are suddenly displayed in the HDMi monitor.
>
>
>
> So I wonder that is is not sufficient to use these two components. If not, am I doing correctly to display somrting in the monitor? I mean, is is true that when I correctly port the libtbm and libtbm for AM335x like exynos, the Tizen’s graphic stack is sufficiently ported?
>
>
>
> I would be very appreciate if something give me any recommendations.
>
>
>
> Best regards.
>
>
>
> Heecheol, Yang.
>
>
> _______________________________________________
> Dev mailing list
> Dev at lists.tizen.org<mailto:Dev at lists.tizen.org>
> https://lists.tizen.org/listinfo/dev





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