Re: scsi freezing problem with NetBSD current

[David Brownlee <abs%NetBSD.org@localhost>]

On Wed, 29 Oct 2008, T. Makinen wrote:

> On Tue, Oct 28, 2008 at 2:17 PM, David Brownlee <abs%netbsd.org@localhost> 
> wrote:
>
> >        As a less invasic change it should be possible to adjust
> >        scsi_dmaok() to return 0 in the CT63 accelerator case...
>
> You're right, that way other systems are not affected by possible change.
>
> >        Hmm, Does the standard falcon System RAM and TT RAM similar
> >        to the TT030? If the standard falcon only has TT RAM then it
> >        should not be too hard to change the DMA behaviour when an
> >        accelerator with additional RAM is enabled.
>
> Falcon can have up 14MB of ST-ram and 512MB (with CT60/63) of TT-ram. So,
> standard Falcon has only ST-ram. I reckon that TT can have up to 12MB of
> ST-ram and 256MB of TT-ram.

        Ah, so presumably both Falcon and TT030 can DMA to ST-ram only?
        Assuming so, and also assuming that NetBSD is working fine for
        scsi on the TT030, we are in one of:
        - Falcon with TT ram needs the same treatment as TT030 and the
          code is treating them differently
        - Falcon with TT ram needs different treatment to TT030 and the
          code is treating them the same
        - Falcon with TT ram needs different treatment to TT030 and the
          code is treating them differently but in a different way :)

        OK, that was stating the obvious, but sometimes that helps...
        Its probably worth taking a pass through the code looking
        for places where it treats the Falcon and TT030 differently
        - there may be a case where the Falcon case is shortcircuiting
        a check for TT-ram because its assuming it never has any.

> Yes, here are links to dmesg files:
> http://koti.welho.com/tmakinen/atari/CT63-netbsd-dmesg
> http://koti.welho.com/tmakinen/atari/Falcon-netbsd-dmesg

        Great - thats nice and clear, ST-ram low, TT-ram >= 0x01000000

        CT63 68060:
            pmap_init:  0: 0060a000 - 00dd4000 (   8167424)
            pmap_init:  1: 01000000 - 20eb2000 ( 543670272)
            total memory = 524 MB

        Falcon 68030:
            pmap_init:  0: 00212000 - 00dd2000 (  12320768)
            total memory = 14336 KB

        Did you have to remove/disable 4MB of RAM for the CT63 case?
        Its probably not relevant, just curious.


> NetBSD current kernel with DEBUG enabled pmap.c:
> http://koti.welho.com/tmakinen/atari/netbsd-current-atari-pmap_DEBUG-BOOT-20081029.gz

        Great - David, could you test? :)

> >        As an aside - NetBSD is always looking for more developers on
> >        the less mainstream platforms :)
>
> Well, I'm new to NetBSD, but I'm happy to offer any help I can :)

        Fixing the scsi bug has been an *excellent* way to start! :)

        There are plenty of different areas in which developers can help

        - Kernel: Fixing bugs, supporting new hardware (in the atari case
          that would be the NETUSBEE, which probably involves building
          one from the plans available, so thats quite a project!),
          performance tuning, or just updating the port to some of the
          newer MI (machine independent) features - such as switching the
          display, keyboard and mouse to wscons with virtual terminals

        - Installer: for recent versions of NetBSD/atari the installer
          doesn't work correctly and needs manual fixups to get the
          installed system working. Ideally this needs someone with
          the skill to fix it _and_ a machine on which they can see
          the issue...

        - X: I don't know if the Atari X server uses the blitter. If not,
          that could be a nice speed boost (Thoughits not going to help
          the TT030 users)

        - Userland/pkgsrc: A Falcon with a CT63 and a chunk of memory
          could probably run firefox (albeit not that fast :), but as
          firefox needs some C++ glue for each architecture, and I don't
          think anyone ever wrote this for gcc4 and NetBSD/m68k.

        - Documentation/help pages - Its always easier for someone else
          to get a system up and running if someone else has done it first
          and left a trail to follow

        Its a question of picking something that interests you and
        running with it. After all, this stuff is supposed to be
        fun (and satisfying)

--
                David/absolute       -- www.NetBSD.org: No hype required --