Messages in this thread | | | From | "Antonino A. Daplas" <> | Subject | Re: [Linux-fbdev-devel] Generic VESA framebuffer driver and Video card BOOT? | Date | Sat, 16 Oct 2004 05:51:38 +0800 |
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On Saturday 16 October 2004 02:36, Kendall Bennett wrote: > "Antonino A. Daplas" <adaplas@hotpop.com> wrote: > > > So what do you guys think? > > > > I'm for it, if you can get the code in the kernel. If not, what > > are the arguments against doing this in userspace? > > At least for the 2.4 kernels it is not possible to run code from user > space early enough in the boot sequence to bring up the video card when > the framebuffer console driver starts. Alan Cox said there is work under > way for 2.6 that might allow this, but it would have to be done very > early in the boot sequence. >
For 2.6, the framebuffer console can activate as early or as late as one wants because fbcon will wait until a framebuffer driver becomes active. In contrast, in 2.4, at least one fb driver needs to be active for the framebuffer console to become active.
> Remember this project is for non-x86 platforms such as PowerPC and MIPS > embedded machines where there is no way to set a graphics mode using the > BIOS before the kernel starts loading (well, you can do something using U- > Boot but a lot of projects don't always use U-Boot). > > > If you remember about 2 years ago, there was a thread which you > > started about vesafbd. From that, I've worked on vm86d which is a > > generic approach to running BIOS code in user space. I stopped > > development on this though, but it should be easy to revive. > > Yes, I am aware of this project. It is a great project for x86 platforms, > but falls short for non-x86 due to the inability to set a basic display > mode prior to user space access becoming available. >
Yes, that is the downside to a userspace solution. How bad will that be? Note that Jon Smirl is proposing a temporary console driver for early boot messages until the primary console driver activates.
> > There is also vesafb-tng. I think it runs BIOS code in kernel > > space. > > I am not familiar with that. Can you point me to a URL? >
http://dev.gentoo.org/~spock/projects/vesafb-tng/
Tony
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