Re: OLS and console rearchitecture

[Alan C. <al...@lx...>]

On Mer, 2004-07-28 at 19:53, Jon Smirl wrote:
> First a basic definition. There are two consoles, the kernel one
> (printk, kdbg, OOPs, etc) and user one (normal console logins). There
> is no requirement that these consoles be handled with the same code
> even though they are today.

Not sure that was consensus 8)

> 2) VGA control - there needs to be a device for coordinating this. It
> would ensure that only a single VGA device gets enabled at a time. It
> would also adjust PCI bus routing as needed. It needs commands for
> disabling all VGA devices and then enabling a selected one. This device
> may need to coordinate with VGA console. You have to use this device
> even if you aren't using VGA console since it ensures that only a
> single VGA device gets enabled.

Some vendors have multiple vga routers according to bus, unclear how
much we care however.

> the mode registers. Early boot and normal user space will use the same
> hotplug apps so they need to be as small as possible (good luck IA64
> and emu86).

IA64 has EFI to get it up initially.

> 11) OOPs will cause an immediate screen clear and painting of the
> system console including the OOPs data. It is not needed to change the
> video mode. Further drawing to the screen will be blocked until SysReq
> returns to normal operation if possible.

No consensus on the screen clear bit - there are actually reasons to
argue against it.

> 16) accelerated, kernel based console drivers are not supported in this
> model. The only in kernel operations are simple ones like CR/scroll,
> clear, print text. It is possible to call existing DRM entry points
> from a kernel thread, but the code needed is complex.

Its not "unsupported" its merely potentially hard because an accelerated
driver may well have to be a DRI client.

> 18) A coordinated system for grouping console devices needs to be
> designed. This will be bad if each distro does it differently. One
> proposal is to use udev to create: /console/1/mouse,
> /console/1/keyboard, /console/1/usb_hub, /console/2/mouse,
> /console/3/keyboard, /console/4/usb_hub, etc.

Another is to use namespace mounts

> 19) SAK - secure attention key. We forgot to talk about this so we need
> a design.

Falls straight out of having the kernel + helper mode setting