Re: [omapdss] fault in dispc_write_irqenable [was: Re: [omap3isp] xclk deadlock]

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Jakub,

On Friday 26 July 2013 21:02:35 Jakub Piotr Cłapa wrote:
> On 26.07.13 17:52, Laurent Pinchart wrote:
> >>> Using omapfb, or...? I hope not
> >>> omap_vout, because that's rather unmaintained =).
> >> 
> >> Laurent's live application is using the V4L2 API for video output (to
> >> get free YUV conversion and DMA) so I guess this unfortunatelly counts
> >> as using omap_vout. Are there any alternatives I should look into? IIUC
> >> to use omapfb I would need to manually copy RGB data into the
> >> framebuffer on each frame.
> > 
> > It should be possible to port the live application to use DRM/KMS with
> > omapdrm for the display side, without requiring any memory copy. That's
> > somewhere on my TODO list, but I won't have time to work on that before
> > way too long.
> I could look into it myself but is there any documentation on omapdrm?
> 
> From what I found libdrm should probably be used but information about it's
> API is really scarce:
> https://dvdhrm.wordpress.com/2012/09/13/linux-drm-mode-setting-api/
> http://dvdhrm.wordpress.com/2012/12/21/advanced-drm-mode-setting-api/
> http://virtuousgeek.org/blog/index.php/jbarnes/2011/10/31/writing_stanalone_
> programs_with_egl_and_
> 
> The last one seems focused on OpenGL so I don't think it applies.
> 
> Are there any good sources to learn about this? Or maybe some pointers on
> where to start with reading source code?

http://events.linuxfoundation.org/sites/events/files/lcjpcojp13_pinchart.pdf

A bit of shameless self-advertising :-)

It would have been clearer with the video, but it seems the talk hasn't been 
recorded :-/ There's also http://www.youtube.com/watch?v=Ja8fM7rTae4 that 
mostly focuses on the kernel side but starts with explanations of the key KMS 
concepts.

As far as KMS is concerned, libdrm is mostly a wrapper, so any documentation 
on the KMS ioctls can help too.

-- 
Regards,

Laurent Pinchart