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From: Scott Wood <scottwood@freescale.com>
To: Alex Zeffertt <ajz@cambridgebroadband.com>
Cc: Liu Dave-r63238 <DaveLiu@freescale.com>, linuxppc-embedded@ozlabs.org
Subject: Re: local_irq_save not masking interrupts
Date: Tue, 26 Sep 2006 11:02:39 -0500	[thread overview]
Message-ID: <45194F1F.7030003@freescale.com> (raw)
In-Reply-To: <451900B0.7010006@cambridgebroadband.com>

Alex Zeffertt wrote:
> Well, mpc832xemds_phy_interrupt_enable() does nothing except call
> request_irq(,,SA_SHIRQ,,).  I suspect that request_irq() is somehow
> reenabling interrupts, but I can't see where it might be doing so.

One possibile way (in 2.6.18; I'm assuming 2.6.11 is similar) is that 
request_irq() calls setup_irq(), which calls register_irq_proc() and 
register_handler_proc(), both of which call proc_mkdir(), which 
eventually calls proc_create(), which calls kmalloc() with GFP_KERNEL. 
This is probably a bug, since request_irq itself uses GFP_ATOMIC, 
indicating an intent for request_irq() to be safely callable in atomic 
context.

Can you disable the interrupts at the device level until the handler is 
in place, and thus avoid the need to disable IRQs at all?

-Scott

  reply	other threads:[~2006-09-26 16:02 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-09-26 10:00 local_irq_save not masking interrupts Alex Zeffertt
2006-09-26 10:19 ` Liu Dave-r63238
2006-09-26 10:28   ` Alex Zeffertt
2006-09-26 16:02     ` Scott Wood [this message]
2006-09-26 16:17       ` Alex Zeffertt
2006-09-26 16:27         ` Scott Wood
2006-09-26 16:42           ` Alex Zeffertt
2006-09-26 16:52             ` Scott Wood
2006-09-27 16:52 ` Esben Nielsen

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