On Wed, 2002-12-04 at 21:47, Sven Luther wrote:
> > > So there is no common zqy of doing this, my docs say something about a
> > > vga control register zhich is accesses trough the sequencer regs. Does
> > > vgafb (or textmode or whatever) not call this when giving the hand to
> > > the fbdev ?
> > No, when a video card goes to graphics mode, it's up to the driver to
> > program the registers. vgacon/vga16fb only touches the standard VGA
>
> So we will have a repeat of the exact same code snipplet in all the
> drivers ? I thought the new API was about having all the common code in
> common and not duplicated in all the drivers. Could we have at least a
> gen_disable_vga function or something such that we could call ?
Not exactly. Different hardware programs those registers differently.
Ie, vga will probably program the crtc regs for 640x400@60. Your
hardware can probably do better than that. So the code cannot be
shared. However, saving and restoring the standard VGA regs can be
common.
>
> > registers (crtc[25], attr[21], seq[5], gfx[9], misc[1]). Usage is pretty
>
> Well, i need to disable the vga output in seq[5], more exactly bit 3
> called "enable VGA display", need to be reset.
>
[...]
>
> Err, it is seq[5], called VGAControlRegister, so it is beyond the
> standard seq registers (seq[0] to seq[5]), right ?
I meant seq[0] to seq[4] are standard VGA regs. So seq[5] is extended.
It's VGAControlRegister in your hardware, it's not used in mine.
>
[...]
> > > Mmm, what about interaction with X ? X also does a save/restore of the
> > > previous (text) mode, when a X driver is _not_ fbdev aware, it will
> > > save/restore the things twice, right ?
> > >
> > Not twice just the current mode it was in when X launched, although it
> > always assumes text mode. Same thing for fbdev, it should only restore
>
> Well, but fbdev will save its state and X will save it again, so the
> saving done in the X driver is not all that important, and i could
> ignore it at first if i already have an fbdev.
If X is running in native mode then it has to save the register state.
Otherwise you cannot switch to a console. If X is running on top of
fbdev, then state restore/saves are done using fb_set_var and
fb_get_var. The registers are not touched, that's the purpose of fbdev.
If you are running vgacon, fbdev, and native X, then yes, fbdev and X
has to do a save of their initial state.
>
> Does this also apply to vesafb ?
Not too sure about this. vesa requires real-mode initialization. Either
you do this at boot time, or fake a real-mode environment like what X
does.
>
> > the state when reference count becomes zero. If the framebuffer console
> > is loaded, the reference count will never be zero unless it is
> > unloaded. If the framebuffer console is not loaded, the only time you
> > will save and restore the state is when some fb-based application
> > attempts to open/close /dev/fbx.
>
> Ok, ...
>
[...]
Tony
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This archive was generated by hypermail 2b29 : Sat Dec 07 2002 - 22:00:20 EST