linux-kernel - Re: drmfb console switching problems/questions

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Date:   Fri, 9 Oct 2020 15:16:25 +0300
From:   stsp <stsp2@...dex.ru>
To:     Thomas Zimmermann <tzimmermann@...e.de>,
        linux-fbdev@...r.kernel.org,
        Linux kernel <linux-kernel@...r.kernel.org>
Subject: Re: drmfb console switching problems/questions

09.10.2020 14:59, Thomas Zimmermann пишет:
> Fbdev exposes the video ram (or a shadow buffer of it) to all
> applications. Only one can draw at the same time. It's a limitation of
> the design. To fix this, your application has to stop drawing when you
> switch consoles.
OK, thanks for info.
Quite a sad news, if you ask me.
Is there any ongoing work at solving that?

Anyway, the fact that fb can
permanently hang, is, I suppose,
another problem - the one that
can't be worked around in an app.
I suspect it is the result of sdl doing
ioctl(console_fd, KDSETMODE, KD_GRAPHICS);
After which, I think, redrawing on a
VC switch became disabled.
Would it make sense to improve SAK
to unfreeze from that? Otherwise its
too easy to hang the screen permanently,
and no way to recover.