[9fans] vga vesa works on mp pc

[9fans] vga vesa works on mp pc

[geoff]

I've just pushed out a small change to /sys/src/9/pc/realmode.c that
allows monitor=vesa to work on multiprocessor pcs without *nomp being
defined in plan9.ini (i.e., you can use all available processors [or
cores] and still use vesa mode).  I've also pushed out new kernels, so
the distribution built tonight should include this fix.

Re: [9fans] vga vesa works on mp pc

[Venkatesh Srinivas]

On Tue, Dec 8, 2009 at 7:05 PM,  <geoff@plan9.bell-labs.com> wrote:
> I've just pushed out a small change to /sys/src/9/pc/realmode.c that
> allows monitor=vesa to work on multiprocessor pcs without *nomp being
> defined in plan9.ini (i.e., you can use all available processors [or
> cores] and still use vesa mode).  I've also pushed out new kernels, so
> the distribution built tonight should include this fix.

Cool, thanks!

If I read this right, you turn off interrupts on just the CPU
executing in realmode. Is the really all that had to be done for vesa
to support MP systems?

-- vs

Re: [9fans] vga vesa works on mp pc

[geoff]

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As far as I can tell, yes, that's all it took.

The old code had been turning off the old 8259 interrupt controllers
used by uniprocessors but didn't disable the lapic on mp systems.

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From: Venkatesh Srinivas <me@acm.jhu.edu>
To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net>
Subject: Re: [9fans] vga vesa works on mp pc
Date: Tue, 8 Dec 2009 20:21:18 -0500
Message-ID: <f75780240912081721o1b706b89wfe71973a125af34e@mail.gmail.com>

On Tue, Dec 8, 2009 at 7:05 PM,  <geoff@plan9.bell-labs.com> wrote:
> I've just pushed out a small change to /sys/src/9/pc/realmode.c that
> allows monitor=vesa to work on multiprocessor pcs without *nomp being
> defined in plan9.ini (i.e., you can use all available processors [or
> cores] and still use vesa mode).  I've also pushed out new kernels, so
> the distribution built tonight should include this fix.

Cool, thanks!

If I read this right, you turn off interrupts on just the CPU
executing in realmode. Is the really all that had to be done for vesa
to support MP systems?

-- vs

Re: [9fans] vga vesa works on mp pc

[erik quanstrom]

On Tue Dec  8 19:07:25 EST 2009, geoff@plan9.bell-labs.com wrote:
> I've just pushed out a small change to /sys/src/9/pc/realmode.c that
> allows monitor=vesa to work on multiprocessor pcs without *nomp being
> defined in plan9.ini (i.e., you can use all available processors [or
> cores] and still use vesa mode).  I've also pushed out new kernels, so
> the distribution built tonight should include this fix.

very nice!

- erik