From: Valentine Barshak <vbarshak@ru•mvista.com>
To: Josh Boyer <jwboyer@linux•vnet.ibm.com>
Cc: linuxppc-dev@ozlabs•org, David Gibson <david@gibson•dropbear.id.au>
Subject: Re: [ PATCH ] PowerPC cascade UIC IRQ handler fix.
Date: Fri, 03 Aug 2007 15:09:29 +0400 [thread overview]
Message-ID: <46B30CE9.5080905@ru.mvista.com> (raw)
In-Reply-To: <20070802150852.39701576@weaponx.rchland.ibm.com>
Josh Boyer wrote:
> On Thu, 2 Aug 2007 13:48:48 +1000
> David Gibson <david@gibson•dropbear.id.au> wrote:
>
>> On Mon, Jul 30, 2007 at 08:35:17PM +0400, Valentine Barshak wrote:
>>> PPC44x cascade UIC irq handler fix.
>>>
>>> According to PPC44x UM, if an interrupt is configured as
>>> level-sensitive, and a clear is attempted on the UIC_SR, the UIC_SR
>>> field is not cleared if the incoming interrupt signal is at the
>>> asserted polarity. This causes us to enter a cascade handler twice,
>>> since we first ack parent UIC interrupt and ack child UIC one after
>>> that. The patch checks child UIC msr value and returns IRQ_HANDLED
>>> if there're no pending interrupts. Otherwise we get a kernel panic
>>> with a "Fatal exception in interrupt" (illegal vector).
>>> The patch also fixes status flags.
>>>
>>> Signed-off-by: Valentine Barshak <vbarshak@ru•mvista.com>
>> Hrm... This doesn't seem like the right fix to me. Instead, I think
>> the cascaded IRQ handler should ack the interrupt on the child first.
>> I'm a little surprised it doesn't at the moment.
>
> Agreed. Anyone going to hack up a patch for that?
>
> josh
Anyways, I don't see why kernel should panic if we get a spurious interrupt.
next prev parent reply other threads:[~2007-08-03 11:10 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-30 16:35 [ PATCH ] PowerPC cascade UIC IRQ handler fix Valentine Barshak
2007-08-02 3:48 ` David Gibson
2007-08-02 20:08 ` Josh Boyer
2007-08-03 11:09 ` Valentine Barshak [this message]
2007-08-03 1:18 ` Benjamin Herrenschmidt
2007-08-03 4:57 ` David Gibson
2007-08-03 6:23 ` David Gibson
2007-08-13 1:08 ` David Gibson
2007-08-13 12:31 ` Valentine Barshak
2007-08-14 1:35 ` David Gibson
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=46B30CE9.5080905@ru.mvista.com \
--to=vbarshak@ru$(echo .)mvista.com \
--cc=david@gibson$(echo .)dropbear.id.au \
--cc=jwboyer@linux$(echo .)vnet.ibm.com \
--cc=linuxppc-dev@ozlabs$(echo .)org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox