From: Geert U. <ge...@li...> - 2001-12-05 09:56:47
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On Tue, 4 Dec 2001, Sottek, Matthew J wrote: > >>The only reason to not allow mmap is that it is hard to force apps > >>to stop writing when they shouldn't. > > >Why to stop them? If we do not provide full virtualization for them, > >we should not put any additional policy on their behavior. > > I'm ok with leaving out policy, but the problem is that we have no > way to notify the client in a timely manner either. They would > have to poll the surface to look at the status. > > So what should be done on a vt switch? > I think it may be ok to zap() someone's mmap during a vt switch but > otherwise make them work out their own policy. vt switches are > slow anyway. That's why for 2.5.x we wanted to disable VT switching for a VT that has its /dev/fb* opened by some application. > I am unsure of how XFree handles this. Does the X server trap the > vt switch sequence, call leave_vt() then switch the vt? The X server indeed installs a VT switch handler, and releases access to the hardware and does the VT switch. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@li... In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds |