Re: Update on video subsystem draft

[Marco Gerards <mgerards@xs4all.nl>]

Vesa Jääskeläinen <chaac@nic.fi> writes:

Hi Vesa,

> I have made some updates to wiki . Changed some parameters from
> grub_[u]int32_t to standard C types ([unsigned] int). Added functions
> used to manage and use render targets.

Nice.  I am not really sure what a render target exactly is.  It would
be really nice if this could be added to the documentation.

> Here is the URL there:
> http://grub.enbug.org/VideoSubsystem

Nice.  I can change some of the coding style so it matches the GCS if
you do not mind.  I am not at home now, I'll do that when I am back
home.

> There is currently some issues with videoterm, screen is only rendered
> when terminal refresh is called. Actually I would like to get more
> information what each terminal function is supposed to do and how they
> should be used. At the moment you have to blindly write commands at this
> point as command line is not refreshed all the time :).

Right, and this behavior should not be changed.  This approach
drastically improves performance for some terminal, I think the same
is true for the frame buffer, right?

> I would like to have some feedback on following areas:
> - Is there all needed video API's present? If not give a description
> what functionality is required and let's see where that should be
> implemented.

I'll look over it Monday, but it looks that way for now.  If we miss
something we can always add it, but it is easier to do that now, of
course.

> - You are of course free to provide optimization ideas. At this point I
> have only considered dirty regions.

Ok.

> - What would be a good way to debug code like this :)... I have VMware
> running here and could use one of it's devices to get debug messages but

For a GNU project VMWare is absolutely not an option.  You are of
course free to do whatever you like, but it is not something that can
be documented.

What I have in mind is extending grub-emu so we can use grub-emu+XFree
to debug the video code.  I could have a look next Monday what needs
to be done in order to accomplish that.

Thanks,
Marco