[PATCH v2 12/12] JUST FOR TEST: Add one-shot trigger to update display

[Daniel Vetter]

On Wed, Jul 01, 2015 at 08:43:01PM +0800, Mark Zhang wrote:
> On 07/01/2015 06:34 PM, Daniel Vetter wrote:
> > On Wed, Jul 01, 2015 at 05:01:52PM +0800, Mark Zhang wrote:
> >> On 07/01/2015 04:36 PM, Daniel Vetter wrote:
> >>> On Wed, Jul 01, 2015 at 04:21:55PM +0800, Mark Zhang wrote:
> >>>> This HACK adds a workqueue to refresh the display periodically.
> >>>> This is used just for testing.
> >>>
> >>> ->dirty is the drm hook you're looking for, it's meant to flush out any
> >>> frontbuffer rendering. Generic kms clients using the dumb buffers (e.g.
> >>> fedora boot splash) use this already.
> >>>
> >>
> >> Oh... I did a grep in drm source and are you talking about
> >> "drm_framebuffer_funcs->dirty"? Yeah, that should work for me.. but that
> >> requires userspace sending IOCTL to trigger, right? Honestly I'm lazy so
> >> I created this HACK so that I don't need userspace to test.
> > 
> > Yeah userspace needs to send ioctl already after each drawing. Generic
> > userspace does that already since it's required by qxl, udl, soon i915 and
> > probably a few others too. fbdev emulation is more annyoing but there's
> > code to move around in these drivers (qxl seems best to me as a starting
> > point) too.
> > 
> 
> Alright, this makes sense. I have no idea about qxl, what I have now is
> an ubuntu running on Tegra114. So I'm wondering what I suppose to do is
> installing qemu on the ubuntu?

My suggestion is just to take the qxl code, move it to the fbdev emulation
helper, make it generic and use it. If you want you can do a
compile-tested patch on top to switch qxl over to the newly added helpers.
No need to install/run qxl itself. Just that qxl seems to have the most
complete solution for what you need.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch