FBIO_WAITFORVSYNC on BBB

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1

Hi,

when I do an ioctl with FBIO_WAITFORVSYNC on my BBblack I got an error (“Inappropriate ioctl for device”). As far as I remember there was also no FBIO_WAITFORVSYNC on the original beagleboard. One had to use omap_dispc_register_isr.

How can I wait for vsync on my BBB?

Robert

2

Hi,

So now I try to enable omapfb und omapdss. I use the kernel source from linux-dev-3.13.6-bone7 and the instructions from
http://processors.wiki.ti.com/index.php/Linux_Core_DSS_User's_Guide#omapdrm

I think I enabled omapdss (see my config), but there is no /sys/devices/platform/omapdss

Where is my error?

Robert

config.txt (116 KB)

3

Well the Sitara am335x use on the bone's doesn't have the "omapfb"
display ip block. On mainline it uses the tilcd driver, based loosely
of the same ip as the davanci da8x-fb driver.

Regards,

4

RobertCNelson:

Well the Sitara am335x use on the bone’s doesn’t have the “omapfb”
display ip block. On mainline it uses the tilcd driver, based loosely
of the same ip as the davanci da8x-fb driver.

Oh, I see. Any chance to get the vsync signal with that in userspace or i a kernel module?

Thanks - Robert

5

RobertCNelson:

Well the Sitara am335x use on the bone’s doesn’t have the “omapfb”
display ip block. On mainline it uses the tilcd driver, based loosely
of the same ip as the davanci da8x-fb driver.

Hi,

it seems the da8xx driver supports the FBIO_WAITFORVSYNC ioctl. I tried to use this driver with my bone. So I compiled a new kernel with da8xx support and removed the tilcdc driver. But now I have no output on hdmi. What did I forget? Do I have to change a dtb file or something like that?

Robert

6

Or you could take Rob Clark's advice.

http://lists.freedesktop.org/archives/dri-devel/2014-March/055477.html

He did write both the omapdrm/tilcd drivers while working for TI, now
he currently works on reverse engineering the qualcom's graphics
stack.

Regards,

7

RobertCNelson:

Or you could take Rob Clark’s advice.

http://lists.freedesktop.org/archives/dri-devel/2014-March/055477.html

First it seems to complicated.
Now I found some really nice examples of how to use drm. You’re right, thats the way to go.

R.