Hi, when we use a true user space console which accesses the gva graphic card at the hardware level (I/O ports, mapped memory), we will face some interesting races with the kernel. I am not so worried about the normal operation (setting cursor etc) although it would be neat to avoid races there, too, but also about other, less common things. For example, when I load a new font, I have to stop the sequencer and map another page into the memory window at 0x0a0000, and during that time a kernel printf could corrupt fonts. I don't think anything really serious can happen (like loosing the state of the video card) as long as all the kernel does is poking into the video memory and accessing the registers for cursor positioning.
But in the future, when we will use a framebuffer, we will face a similar problem in that the kernel messages will not appear but as dust in the background picture or so. I am not sure we can do anything reasonable about it. Disabling the kernel messages would be the cure for corruption, but it might make you miss out on important messages from the kernel. Maybe the kernel could check the register settings before writing, if they appear to be sane (having page0 and page1 mapped at the right position in odd/even mode). Not sure what it could do if they are not sane, though. Why doesn't every PC have a serial console for kernel messages built in? Thanks, Marcus -- `Rhubarb is no Egyptian god.' Debian http://www.debian.org [EMAIL PROTECTED] Marcus Brinkmann GNU http://www.gnu.org [EMAIL PROTECTED] [EMAIL PROTECTED] http://www.marcus-brinkmann.de _______________________________________________ Bug-hurd mailing list [EMAIL PROTECTED] http://mail.gnu.org/mailman/listinfo/bug-hurd
