Messages in this thread | | | Date | Wed, 4 Dec 2002 11:28:20 +0100 | Subject | Re: [Linux-fbdev-devel] [PATCH] FBDev: vga16fb port | From | Sven Luther <> |
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On Wed, Dec 04, 2002 at 05:08:53PM +0500, Antonino Daplas wrote: > On Wed, 2002-12-04 at 12:32, Sven Luther wrote: > > On Tue, Dec 03, 2002 at 05:22:35PM +0500, Antonino Daplas wrote: > > > > 2) The ability to go back to vga text mode on close of /dev/fb. > > > > Yes fbdev/fbcon supports that now. > > > > > > I'll take a stab at writing VGA save/restore routines which hopefully is > > > generic enough to be used by various hardware. No promises though, VGA > > > programming gives me a headache :( > > > > BTW, i am writing a fbdev for a card where the docs tell me to disable > > vga output before enabling graphical output. Does i need to do this in > > the fbdev i write, or is it already handled by the vga layer, or > > whatever ? > > Most cards with a VGA core needs to disable the VGA output before going > to graphics mode. Disabling VGA output is hardware specific, and is > usually automatic when you go to graphics mode.
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 ?
> Because James wrote the fb framework to be very modular, then you must > be careful to save/restore the initial video state when loading or > unloading. Theoretically, a driver should load, but not go to graphics > mode immediately. Only upon a call to xxxfb_set_par() should the driver > do so. Before going to graphics mode, that's were you save the initial > state. Have a reference count or something to keep track of the number > of users, and when this reference count becomes zero, restore the > initial state. You should be able to do this by hooking these routines > in fb_open() and fb_release().
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 ?
> The one I submitted (and a revised one I'm going to submit soon) should > be able to restore the VGA text/graphics mode. Complement this with > your hardware's extended state save and restore routines and you should > be able to load/use/unload your driver repeatedly :-).
Ok, i will try.
Friendlmy
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