Re: 2.6.12 PREEMPT_RT && PPC

[Gene Heskett <gene.heskett@verizon.net>]

On Thursday 21 July 2005 07:45, Gene Heskett wrote:
>On Thursday 21 July 2005 00:48, john cooper wrote:
>>Ingo,
>>     Attached is a patch for 51-28 which brings PPC
>>up to date for 2.6.12 PREEMPT_RT.  My goal was to
>>get a more recent vintage of this work building and
>>minimally booting for PPC.  Yet this has been stable
>>even under our internal stress tests.  We now have
>>this running on 8560 and 8260 PPC targets with a few
>>others in the pipe.
>>
>>Remaining are a few known BUG asserts to address,
>>but as we've historically been chasing seemingly
>>PPC-specific (or perhaps usage-specific) problems in
>>a fairly old code base it seemed high time to move
>>forward.  I've also applied the same patch to 51-33
>>which not being very far from 51-28 did apply clean,
>>builds, boots, and appears equally stable as 51-28.
>>
>>In the process of producing the patch I stumbled
>>across a change introduced in 51-15 where in the
>>case of PREEMPT_RT it appears hw_irq_controller.end()
>>is never being called at the end of do_hardirq().
>>This appears to be an oversight in the code and
>>the existing PPC openpic code does register a end()
>>handler which it expects to be called in order to
>>terminate the interrupt.  Otherwise interrupts at
>>the current level are effectively disabled.
>
>Humm, I wondering out loud if this is the video dma failure in
> tvtime? Anyway, it applied cleanly over -33, and is building now,
> set for mode=4.
>
>Rebooted, running it now, and no, this wasn't it, tvtime still has a
>BSOD with good audio.  However, where before I got about 4-6 cx88
>interrupts for a short run of tvtime each time I ran it, now I'm
>showing only 4 regardless.  Even if I leave it runnng, the count is
>stuck at 4.
>
>I wonder if those 4 are associated with the initial insmod?
>I've rmmod cx8800 cx88-dvb, then modprobe cx88-dvb which then shows
>the cx8800 module (unused) in an lsmod, but a cat of
> /proc/interrupts now shows 2 of them:
>
>17:          4  IO-APIC-level  [........../  0]  cx88[0], cx88[0]
>
>But I'll run this for a bit & see what else falls off on the
>curves. :)

As an addendum, I've found that xawtv's video works, but its audio 
doesn't.  And the IRQ count for cx88 is being incremented, but not at  
an IRQ per video frame, maybe around 10/second.

 17:       8972  IO-APIC-level  [........../ 58]  cx88[0], cx88[0]

Thats for about a (SWAG) 10 minute run while I tried to find some 
audio.

The video looks ok considering its never twice same color.

So now we know its not the cx88 stuff, but tvtime thats failing, and 
only in mode 4 so Billy Biggs has been added to the CC:

-- 
Cheers, Gene
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
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message by Gene Heskett are:
Copyright 2005 by Maurice Eugene Heskett, all rights reserved.
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