Messages in this thread |  | | | From | (H. Peter Anvin) | | Subject | Re: keyboard raw mode? | | Date | 21 Jun 1998 19:58:16 GMT |
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Followup to: <199806210559.BAA07250@saturn.cs.uml.edu> By author: "Albert D. Cahalan" <acahalan@cs.uml.edu> In newsgroup: linux.dev.kernel > > Mathieu Bouchard writes: > > > afaik, there is nothing at the kernel level to prevent a crash of the > > keyboard when running root or suidroot programs such as the X Server, > > DosEmu, SvgaLib-based programs (mostly games and demoscene stuff)... > > I looked into this a bit. The problem is that keyboard mode is > associated with the device, not the file descriptor. It seems that > the device does the keyboard code translations before putting data > into a TTY flip buffer, from which multiple processes can read the > data. To fix, conversion must happen on the other side of the TTY > buffer or the TTY buffer must be eliminated AFAIK. >
Why?
> > > keyboard anymore, and no mouse either because X overrides GPM > > (GPM has a feature for rebooting the system in case of keyboard > > lock, but if GPM is disabled by X, it's worthless, and anyway, > > the mouse is not the responsibility of the kernel). > > No, the kernel should have better mouse support. SysV systems have > an event queue that includes both mouse and keyboard. If that is > not offered, then both mouse and keyboard need to supply high-resolution > timestamps so that user-space can be sure of event order. Without > the combined queue and/or timestamps, keystrokes can go to the wrong > window and a shift-click might be seen as shift followed by click. > I think GGI's EvStack provides both. Real-time scheduling can hide the > problem most of the time, but it doesn't completely eliminate the race. >
Timestamps are a good idea anyway.
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