From: Sergei Shtylyov <sshtylyov@ru•mvista.com>
To: Randy Vinson <rvinson@mvista•com>
Cc: "linuxppc-dev@ozlabs•org" <linuxppc-dev@ozlabs•org>
Subject: Re: [RFC] 85XX: Allow 8259 cascade to share an MPIC interrupt line.
Date: Fri, 08 Jun 2007 00:04:19 +0400 [thread overview]
Message-ID: <466864C3.2000303@ru.mvista.com> (raw)
In-Reply-To: <4668628A.30401@mvista.com>
Randy Vinson wrote:
>>>After processing a possible 8259 interrupt, the 8259 cascade handler
>>>calls handle_fasteoi_irq to perform the actions noted above. However,
>>>with the 8259 cascade handler hooked to the interrupt, the threaded IRQ
>>>handler doesn't recognize it as one of the 4 standard generic IRQ types
>>>and calls the threaded version of do_irq instead of the threaded fasteoi
>>>handler.
>> Ah, that's it!
>>>Once the threaded do_irq handler completes the action list, it
>>>uses the .end routine to restart the interrupt flow. Pointing .end to
>>>the standard MPIC unmask routine allows it to balance the interrupt mask
>>>operation performed by handle_fasteoi_irq before it scheduled the IRQ
>>>thread.
>> Well, but when MPIC's eoi() method is called then? :-O
> It's called from handle_fasteoi_irq as I described in the "basics" ;)
Indeed, I somehow thought eoi() is out of the threaded exit path of
handle_fasteoi_irq() -- but it hasn't always been that way! So, it's probably
a painful memories of my past quarrel with Ingo over fasteoi breakage that
played a trick with me here. ;-)
> Randy V.
WBR, Sergei
prev parent reply other threads:[~2007-06-07 20:02 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-06-07 0:47 [RFC] 85XX: Allow 8259 cascade to share an MPIC interrupt line Randy Vinson
2007-06-07 15:30 ` Jon Loeliger
2007-06-07 18:04 ` Randy Vinson
2007-06-07 17:14 ` Sergei Shtylyov
2007-06-07 19:25 ` Randy Vinson
2007-06-07 19:41 ` Sergei Shtylyov
2007-06-07 19:54 ` Randy Vinson
2007-06-07 20:04 ` Sergei Shtylyov [this message]
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