On Tue, 14 Mar 2000, Sven LUTHER wrote:
> On Tue, Mar 14, 2000 at 11:02:27AM -0500, James A Simmons wrote:
> >
> > > > Here is the main reasons why I have it so only one app can open /dev/fb at
> > > > a time. Its called SMP. Consider two apps running at the same time both
> > > > with /dev/fb opened. Problem:
> > > >
> > > > 1)
> > > > Both apps mmap the MMIO region. Both program the accel engine at the
> > > > same. Hey the card locks up.
> > > >
> > > > 2)
> > > > DRI and fbdev MMIO region. DRI is using accel engine. Some app running
> > > > from a xterm mmaps MMIO region then uses accel engine. The card locks up.
> > > >
> > > > 3)
> > > > Someone runs fbset while the X server is using accel engine via /dev/fb
> > > > or DRI. Card locks up. You should only change the mode when the accel
> > > > engine is idle.
> > > >
> > > >
> > > > Now do people agree with me that /dev/fb should only be opened once.
> > >
> > > Err, ...
> > >
> > > not, there is no reason i should not be able to change mode of Xfree-fbdev
> > > whit fbset, not sure it will work, but still that is xfree who is broken.
> >
> > No the X server should change the modes. Their is also the problem of two
> > apps trying to set the video mode at the same time. Broken apps shouldn't
> > force the kernel to be broken.
>
> Too, bad, ...
>
> fbset has a nice interface i understand, while the Xserver offer no such
> thing, appart from the limited ctr+alt+[+-] stuff.
Yeah I know. It could be better.
> > Security :) One of the goals is to allow anyone to run a app on /dev/fb.
> > No more root.
>
> I do not understand you here, ...
>
> whats the problem with me wanting to know what resolution my xserver is
> currently running at ?
First their is app called xdpyinfo that does this. If you need a program
to know this their are Xlib function calls that do this. Look at xdpyinfo
source code.
> i just do a fbset -i on it, and then i can for example set the console fbdev
> mode to exatcly the same to avoid slow switching between the console and X.
Thats fine. You open /dev/fb and set the mode then close /dev/fb. Then you
VT switch to another VT and start X.
"Look its a text editor, no its a OS, no its Emacs"
James Simmons (o_
fbdev/gfx developer (o_ (o_ //\
http://www.linux-fbdev.org (/)_ (/)_ V_/_
http://linuxgfx.sourceforge.net
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