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Re: some console code checked in

From: Roland McGrath
Subject: Re: some console code checked in
Date: Mon, 18 Mar 2002 03:12:54 -0500 (EST)

I checked in some build nit fixes, and started a ChangeLog file.
Just some quick first thoughts, not having read all the code.

I think all the terminal emulation stuff belongs in the common layer and
not in the vga code.  All that stuff would be the same for a different sort
of output device.  Each output device can just have a few calls for move
cursor, scroll, clear space, write chars, etc.

About LEDs: in the PC keyboard hardware they are part of the same hardware,
so it needs to be the same driver as handles the keyboard input.  It will
be the same story for USB keyboards and such as well.  So it will be either
a device_set_status call or just output bytes to the kbd device to diddle
the state (write a new bitmask of lit LEDs).  We can just punt this until
we have a real keyboard driver in oskit-mach, but it would be good to
factor it into the vc switching code and so on from the start anyway.

About the bell, you can see the oskit code for how it's handled in the PC
hardware (pc_speaker).  It's just io ports that you use to set the
frequency and turn the tone on, then you wait, then you turn it off.  I
don't think anything else uses those particular io ports (0x61 turns the
speaker on, 0x48 controls the timer that drives the tone frequency), so
console could just diddle them directly as it does for VGA (though there is
the timing question--it would suck to have your speaker keep beeping while
something gets paged in before console runs again to turn it off).  

Visual bell is certainly a feature that many people like.  Ultimately, you
want to have the bell behavior be an independent pluggable thingabob like
screensavers so people can have it do something visually fancy, or contact
fancy sound hardware, or turn on the vibrator in their pants, or whatever.

What makes you think that trivfs won't work and you need netfs?

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