From: Jaroslav Franek <jarin.franek@post.cz>
Date: Fri, 6 Jun 2008 09:04:19 +0000 (+0200)
Subject: sound: emu10k1 - fix system hang with Audigy2 ZS Notebook PCMCIA card
X-Git-Tag: v2.6.26-rc6~33^2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=868e15dbd2940f9453b4399117686f408dc77299;p=pandora-kernel.git

sound: emu10k1 - fix system hang with Audigy2 ZS Notebook PCMCIA card

When the Linux kernel is compiled with CONFIG_DEBUG_SHIRQ=y,
the Soundblaster Audigy2 ZS Notebook PCMCIA card causes the
system hang during boot (udev stage) or when the card is hot-plug.
The CONFIG_DEBUG_SHIRQ flag is by default 'y' with all Fedora
kernels since 2.6.23. The problem was reported as
https://bugzilla.redhat.com/show_bug.cgi?id=326411

The issue was hunted down to the snd_emu10k1_create() routine:

/* pseudo-code */
snd_emu10k1_create(...) {
	...
	request_irq(... IRQF_SHARED ...) {
		register the irq handler
		#ifdef CONFIG_DEBUG_SHIRQ
		call the irq handler: snd_emu10k1_interrupt() {
			poll I/O port   // <---- !! system hangs
			...
		}
		#endif
	}
	...
	snd_emu10k1_cardbus_init(...) {
		initialize I/O ports
	}
	...
}

The early access to I/O port in the interrupt handler causes
the freeze. Obviously it is necessary to init the I/O ports
before accessing them. This patch moves the registration of
the irq handler after the initialization of the I/O ports.

Signed-off-by: Jaroslav Franek <jarin.franek@post.cz>
Acked-by: James Courtier-Dutton <James@superbug.co.uk>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---

Reading git-diff-tree failed