From: Kevin Diggs <kevdig@hypersurf•com>
To: linuxppc-dev@ozlabs•org
Subject: Re: pmac_zilog debugging ...
Date: Mon, 17 Nov 2008 02:21:47 -0800 [thread overview]
Message-ID: <492145BB.7080904@hypersurf.com> (raw)
In-Reply-To: <1226912422.7178.228.camel@pasglop>
Benjamin Herrenschmidt wrote:
>
>
> That's definitely strange. I would expect the kernel to be able to get
> interrupts fast enough to service a 1200 bauds serial port. Maybe
> there's something else wrong, or an other driver causing undue interrupt
> latencies....
>
As far as I can see the system is NOT busy. I see no evidence of excessive
interrupt loading. It does have an Adaptec 2940 u2w SCSI card, an ATI video card,
and a USB/firewire card. The SCSI card has some disks on it. The other two cards
are unused. I guess, in theory, something in my 2.6.27 kernel could be causing one
of the two unused cards to throw spurious interrupts?
I still think the hardware is mis-behaving.
> Out of curiosity, check that IDE properly unmasks interrupts (hdparm
> -u1 /dev/hda).
>
This is an 8600. It is SCSI only (the onboard controller is the MESH).
>
>> So, I'm on board with this approach. Since I don't really know what I am
>>doing, how do you recommend I proceed?
>
>
> Google for a document called MacTech.pdf which contains various
> documentations for bits of the ancestor of the IO chip in your machine,
> along with a description of the DBDMA engine :-) Something else you can
> do is to look at how it's properly used by other drivers such as bmac
> and look at some of the darwin source code for reference on how the HW
> works.
>
where might one find older Darwin source?
> Cheers,
> Ben.
>
> _______________________________________________
>
next prev parent reply other threads:[~2008-11-17 10:22 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-07 21:38 pmac_zilog debugging Kevin Diggs
2008-11-07 22:23 ` Benjamin Herrenschmidt
2008-11-13 11:38 ` Kevin Diggs
2008-11-13 21:44 ` Benjamin Herrenschmidt
2008-11-13 22:29 ` Kevin Diggs
2008-11-14 1:00 ` Benjamin Herrenschmidt
2008-11-17 8:37 ` Kevin Diggs
2008-11-17 9:00 ` Benjamin Herrenschmidt
2008-11-17 10:21 ` Kevin Diggs [this message]
2008-11-17 11:40 ` Benjamin Herrenschmidt
2008-11-08 5:52 ` Paul Mackerras
2008-11-08 10:46 ` Benjamin Herrenschmidt
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