Re: [PATCH 0/7] Detaching fbcon

From: Jon Smirl
Date: Tue Jun 06 2006 - 16:59:33 EST


On 6/6/06, Antonino A. Daplas <adaplas@xxxxxxxxx> wrote:
Jon Smirl wrote:
> On 6/6/06, Jon Smirl <jonsmirl@xxxxxxxxx> wrote:
>> On 6/6/06, Antonino A. Daplas <adaplas@xxxxxxxxx> wrote:
>> > Overall, this feature is a great help for developers working in the
>> > framebuffer or console layer. There is not need to continually
>> reboot the
>> > kernel for every small change. It is also useful for regular users
>> who wants
>> > to choose between a graphical console or a text console without
>> having to
>> > reboot.
>>
>> Instead of the sysfs attribute, what about creating a new escape
>> sequence that you send to the console system to detach? Doing it that
>> way would make more sense from a stacking order. It just seems
>> backwards to me that you ask a lower layer to detach from the layer
>> above it. The escape sequence would also work for any console
>> implementation, not just fbcon.
>>
>> If console detached this way and there was nothing to fallback to
>> (systems without VGAcon), it would know not to try and print anything
>> until something reattaches to it.
>
> Another thought, controlling whether console is attached or not is an
> attribute of console, not of fbcon.

If the console attached fbcon, then I agree that console should decide
when to detach fbcon. But that's not what happens, it's fbcon that
attaches itself.

It's not that you're wrong, it's just how the current vt/console layer
works. If someone do decide to add this feature to the vt/console layer,
then I'm more than willing to have fbcon support that as well.

This is just kind of twisted since console increments the fbcon ref
count. Is /dev/console a real device, it that where the sysfs
attribute should go?

How is the stack maintained of what was previously bound to console?
What if I unbind fbcon on a system that doesn't have VGAcon for a backup?

--
Jon Smirl
jonsmirl@xxxxxxxxx
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