Re: [PATCH] vt: Drop K_OFF for VC_MUTE

From: Arthur Taylor
Date: Wed Dec 12 2012 - 13:08:10 EST


>> Drop the K_OFF handling and replace it with a new "mute" ioctl pair.
>> Anybody using K_OFF would already need to be prepared to handle it
>> throwing -EINVAL for old kernel compatibility, so userspace will degrade
>> gracefully.
>
> Interesting theory. It may degrade but it'll degrade to a state worse
> than current.

AFAIK the only consumer of K_OFF is Xorg, as I wrote both the
patches, and Xorg will degrade nicely if K_OFF doesn't work.

I'm confused why g-c-c is trying to set the virtual console keyboard
mode, as it is completely the wrong thing to do. X never wants its
virtual console set to K_UNICODE, which is the same as K_XLATE, but in
unicode. Doing so causes the kernel to buffer lines and handle things
like CTRL-C and ALT-Fn.

As this is a per-virtual console setting, setting it on the current VT
where X is running has no effect on other virtual consoles.

Modern X uses the input event subsystem directly and has no need for
the virtual console to be involved with input. Ancient X required that
the virtual console be in K_RAW.

-Art
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