Messages in this thread | | | Subject | Re: kill -9 <pid of X> | Date | Thu, 13 Aug 1998 13:40:00 +0200 | From | Olaf Titz <> |
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> Before anybody starts trying to convince me that there is kernel help > needed, they'd better have their facts straight.
To ensure system stability, all hardware access has to be confined to device drivers which run in the kernel, so that they are sanity-checked and when a process exits prematurely, it is ensured the hardware state is not left undefined. That's the traditional reasoning and I think it is valid even if a heap of video drivers in the kernel would be as messy as the current heap of network drivers. ;-)
If we wouldn't follow that, we never had a parport driver in the kernel. That one in the simplest case doesn't need interrupts or DMA (other reasons for putting stuff in the kernel) and if you only can access the parport I/O addresses, you can damage much less than with access to a video card. At worst you wegde the printer[1]. BRSing a printer is nothing compared to BRSing a computer...
Everything else belongs in user space. Really I think the proper way to make an X server is to have a framebuffer device spiced with acceleration ioctls[2], and let the X server use that. But that needs some kernel support, limited mostly to mode switching and stuffing commands into the accelerator parts. It would be messy but it wouldn't necessary _have_ to be as messy as XFree86 is currently.
VGAs which don't support a linear framebuffer are out here (and as a band-aid can still be used with the old XFree86 servers).
olaf
[1] My BIOS doesn't properly initialize the printer port. The printer gets wedged by reboot until the parport driver is initialized, which means I have to build that into the kernel. My old board worked with that as a module. Oh well.
[2] I don't know what's going on in the video-drivers-in-kernel camp currently, I'm just stating how _my_ model would look like.
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