Re: [PATCH] Fixed ieee1275 console

[Robert Millan <rmh@aybabtu.com>]

On Wed, Oct 10, 2007 at 11:57:44PM +0200, Marcin Kurek wrote:
> > In your code there's a condition in which _serial is set to 0 and _fb is
> > left unset (as 0).  Is this intended?  Sounds like a bug.
> 
> Not this is not a bug. We can heve 3 cases here:
> 
> 1) True serial console. In this case  recent versions of OF set stdout
> name and type to "serial" (_serial = 1, _fb = 0) In this case we want
> to use simple frames.
> 
> 2) On the screen terminal without framebuffer (fb-mode not existing or
> set to 0x0x0) In this case we will get type "serial" (As it not
> supports pixel operations) and name "display" as this is not real
> serial console. (_serial = 0, _fb = 0) In this case we can use cp437
> frames.
> 
> For old versions of OF this case need to catch "bootconsole" too.
> 
> 3) Console with framebuffer (fb-mode != 0x0x0) In this case we will
> get type to "display" or "vga" (_serial = 0, _fb = 1) In this case we
> can not use cp437 frames as vga font used by OF maps only first 127
> characters ;( I put this in to separate case as we can still use
> framebuffer interface to draw some frames or try to load a working
> font, etc.
> 
> I use 'true serial' as a safe default if detection fails for some reasons.

Ok but do we really need to make that distinction?  Perhaps it would be simpler
to define a structure that only cares about charset capability, and make code
that plays with charsets just check that, without caring if it's a serial
cable or a vga with old firmware, etc.

And possibly this could be integrated with your proposed use of
grub_term.flags ? (I'm not sure if that would make sense, but it would be
nice to simplify if possible)

-- 
Robert Millan

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<DRM> What use is a phone call, if you are unable to speak?
(as seen on /.)