BBB Weston + sgx + ti-omap3-sgx-wayland-wsegl + HDMI: display wrapping issue

Hi all,

I’ve put together a yocto build for the BBB which uses weston+wayland driven by the sgx kernel modules.

I’m using this as a wrapper around libEGL: I’m using some bit bake hackery based on:

I’m running ti’s 3.12 staging kernel with the GFX release.

It all seems to work, but I’m seeing some strange display wrapping on the monitor I’ve got hooked up. Essentially, “sometimes” the display rotates/shifts left by a few pixels. It’s always the same amount, always the same shift direction, and either displays properly or has this defect. It shows up and goes away as I change what is rendered on the screen (typing, moving windows) with no apparent pattern.

Here’s a photo showing the slight wrap-around that I’m describing here. Look at the right edge of the screen:

I’m wondering if this is a known HDMI issue? Or a libgles-omap3 issue that needs to be hacked around? Or something else?

The screen wrap seems to be an issue with the rev C boards. I’ve never noticed it with my rev A5C bbb.
Quickly scrolling up and down a directory listing in mc running in a vc causes the screen to often jump back and forth.
As suggested in this ti forum thread, sitara_arm forum, try adjusting the value in the REG_PR_OLD_COUNT register.
I’ve found a value below 0x68 works well on mine but I expect it depends on what software you have running.

Sorry to hijack this: You got drm-gbm branch to work? Which backend are you using?

Andreas (schnitzeltony)

After I posted this I realized that while I was building the drm-gbm
branch, weston was using the fbdev backend, and thus not passing
anything through the accelerated part :frowning:

Aargh - and I hoped you could inspire me :slight_smile:

FWIW: fbdev backend should work (more or less) with --use-gl (this
option is not mentioned in weston --help) and master branch