Re: SOLVED: mesh SCSI bus locks hard on 7500 when burning a CD-R in

Re: SOLVED: mesh SCSI bus locks hard on 7500 when burning a CD-R in

[Robert E Brose II]

User Michael Schmitz said:

> Disconnect and reselect are implemented in the ESP driver which was used
> as template for the 68k Mac 53C9x driver at one time. Maybe take a
> page or two from these drivers to implement disconnect. That driver uses a
> trick that might help avoiding the data direction lockup with MESH as
> well: the chip is programmed for the whole arbitration/selection/command
> phases but will interrupt right before data phase, at which point you
> could check the data direction before setting up the DMA (assuming the
> target asserts the data direction after seeing the command byte). One
> additional interrupt taken. No additional overhead if you skip this step
> for some well known commands like WRITE_* and READ_* :-)

This data direction table thing rings a bell. I helped implement a
scsi driver on SVR4 for the DPT (EATA) and it had the tables.
By SVR4.2 they were gone.

I noticed the same problems as Daniel writing dao CD's on my 7500.
I have the hard drive on the mesh and the tape drive and cdrw on
the 53c94.

In a post about 6 months ago I noted that the 53c94 didn't appear to
do disconnect because I couldn't write a CD even at 1x on a 7200.

As expected though, the cdrw will write on the 7500 on the 53c94
(not in dao) because the hard drive being on the mesh doesn't have to
wait for the 53c94 cd data transfer to finish before doing another read.

The tape drive was another clue. It did endless start/stops on the
7200 53c94 but on the 7500 53c94 by itself, streams nicely.

Thanks Daniel for digging this stuff out. A fix for the 53c94
disconnect problem would sure make the 7200 a  better platform.

Bob
--
Robert E. Brose II    N0QBJ
http://www.jriver.com/~bob/
bob@kunk.jriver.com

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Re: SOLVED: mesh SCSI bus locks hard on 7500 when burning a CD-R in

[Michael Schmitz]

> Thanks Daniel for digging this stuff out. A fix for the 53c94
> disconnect problem would sure make the 7200 a  better platform.

Unless Paul had specific reasons not to use the generic NCR53C9x driver
code for the mac53c94 driver, I'd say we should start from scratch using
the generic driver code base. I know it looks messy and a lot of the Sparc
cruft should be stripped out (IIRC Sparc still uses esp.c) but it might be
worth the trouble.

Problem is, the only Powermacs I could use for testing are a 7100 and a G3
(233 MHz desktop). Which one of these does use the 53C94?

	Michael


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Re: SOLVED: mesh SCSI bus locks hard on 7500 when burning a CD-R in

[Robert E Brose II]

User Michael Schmitz says:
>
> Unless Paul had specific reasons not to use the generic NCR53C9x driver
> code for the mac53c94 driver, I'd say we should start from scratch using
> the generic driver code base. I know it looks messy and a lot of the Sparc
> cruft should be stripped out (IIRC Sparc still uses esp.c) but it might be
> worth the trouble.
>
> Problem is, the only Powermacs I could use for testing are a 7100 and a G3
> (233 MHz desktop). Which one of these does use the 53C94?

I just did some online searching and wasn't able to find out. I
think the easiest way to find out would be to boot a kernel on each
machine and check the dmesg. You could just use a YDL or LPPC install
CD on the G3-233 but the 7100 is NuBus so you'd need to try the
experimental NuBus kernel.

I have a spare 7200 which I can use for testing as well.

Bob
--
Robert E. Brose II    N0QBJ
http://www.jriver.com/~bob/
bob@kunk.jriver.com


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Re: SOLVED: mesh SCSI bus locks hard on 7500 when burning a CD-R in

[Takashi Oe]

On Mon, 5 Feb 2001 20:28:21 +0100 (CET), Michael Schmitz
<schmitz@opal.biophys.uni-duesseldorf.de> wrote:

> Problem is, the only Powermacs I could use for testing are a 7100 and a
> G3
> (233 MHz desktop). Which one of these does use the 53C94?

7100.  G3 desktop comes with mesh.


Takashi Oe

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Re: SOLVED: mesh SCSI bus locks hard on 7500 when burning a CD-R in

[Iain Sandoe]

> 7100.  G3 desktop comes with mesh.

I have 9600 with both MESH & 53C94 - both have devices - and my CD-RW is on
that machine (not tried under linux yet).

So, time willing, I'm happy to test things.
ciao,
Iain.

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Re: SOLVED: mesh SCSI bus locks hard on 7500 when burning a CD-R in

[Tony Mantler]

At 1:38 AM -0600 2/6/2001, Iain Sandoe wrote:
>> 7100.  G3 desktop comes with mesh.
>
>I have 9600 with both MESH & 53C94 - both have devices - and my CD-RW is on
>that machine (not tried under linux yet).
>
>So, time willing, I'm happy to test things.

Ditto. The latest BK-Rsync seems to be working on my 9600/200mp, so I'll be
able to test new scsi drivers too.

On the plus side, my root volume is on a Promise IDE card, so no danger in
messing that up. :)

I've got a CDRom on the MESH side and a zip drive on the 53c94 side, plus a
DDS-1 tape drive that I can put on either. Should be disconnects-o-plenty
there.


Cheers - Tony 'Nicoya' Mantler :)


--
Tony "Nicoya" Mantler - Renaissance Nerd Extraordinaire - nicoya@apia.dhs.org
Winnipeg, Manitoba, Canada           --           http://nicoya.feline.pp.se/


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Re: SOLVED: mesh SCSI bus locks hard on 7500 when burning a CD-R in

[Michael Schmitz]

> > 7100.  G3 desktop comes with mesh.

Too bad. I don't think I have space for yet another kernel tree on my
Lombard, or the stomach to get involved with the Nubus kernel.

> I have 9600 with both MESH & 53C94 - both have devices - and my CD-RW is on
> that machine (not tried under linux yet).
>
> So, time willing, I'm happy to test things.

I'll try to cook up someting reasonably safe...

	Michael


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Re: SOLVED: mesh SCSI bus locks hard on 7500 when burning a CD-R in

[Daniel Eisenbud]

On Tue, Feb 06, 2001 at 06:41:52PM +0100, Michael Schmitz <schmitz@opal.biophys.uni-duesseldorf.de> wrote:
>
> > > 7100.  G3 desktop comes with mesh.
>
> Too bad. I don't think I have space for yet another kernel tree on my
> Lombard, or the stomach to get involved with the Nubus kernel.
>
> > I have 9600 with both MESH & 53C94 - both have devices - and my CD-RW is on
> > that machine (not tried under linux yet).
> >
> > So, time willing, I'm happy to test things.
>
> I'll try to cook up someting reasonably safe...

The patch I sent should fix the immediate problem with burning CD's in
disk-at-once mode.  It works for me.  But clearly there's room for SCSI
improvements so that this doesn't happen again with other new commands.

-Daniel

--
Daniel E. Eisenbud
eisenbud@cs.swarthmore.edu

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Re: SOLVED: mesh SCSI bus locks hard on 7500 when burning a CD-R in

[Michael Schmitz]

> >
> > I'll try to cook up someting reasonably safe...
>
> The patch I sent should fix the immediate problem with burning CD's in
> disk-at-once mode.  It works for me.  But clearly there's room for SCSI

I understood that :-)

> improvements so that this doesn't happen again with other new commands.

It's more about adding disconnect support to the 53C94 PPC driver at the
moment. I'm not touching MESH 'cause I've got no experience with that
code, and no specs. I'm a bit familiar with the 53C9x series chips in the
old Macs.

	Michael


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Re: SOLVED: mesh SCSI bus locks hard on 7500 when burning a CD-R in

[Geert Uytterhoeven]

On Tue, 6 Feb 2001, Michael Schmitz wrote:
> > > 7100.  G3 desktop comes with mesh.
>
> Too bad. I don't think I have space for yet another kernel tree on my
> Lombard, or the stomach to get involved with the Nubus kernel.

Come on, Michael! The Nubus kernel is just a mix of what you're used to. And
food got mixed in the stomach anyway :-)

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds


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