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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>
This commit is contained in:
Jaroslav Franek 2008-06-06 11:04:19 +02:00 committed by Takashi Iwai
parent 53c8ba9540
commit 868e15dbd2
1 changed files with 8 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
sound/pci/emu10k1/emu10k1_main.c
View File

@ -1818,13 +1818,6 @@ int __devinit snd_emu10k1_create(struct snd_card *card,
}
emu->port = pci_resource_start(pci, 0);
if (request_irq(pci->irq, snd_emu10k1_interrupt, IRQF_SHARED,
"EMU10K1", emu)) {
err = -EBUSY;
goto error;
}
emu->irq = pci->irq;
emu->max_cache_pages = max_cache_bytes >> PAGE_SHIFT;
if (snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, snd_dma_pci_data(pci),
32 * 1024, &emu->ptb_pages) < 0) {
@ -1887,6 +1880,14 @@ int __devinit snd_emu10k1_create(struct snd_card *card,
emu->fx8010.etram_pages.area = NULL;
emu->fx8010.etram_pages.bytes = 0;
/* irq handler must be registered after I/O ports are activated */
if (request_irq(pci->irq, snd_emu10k1_interrupt, IRQF_SHARED,
"EMU10K1", emu)) {
err = -EBUSY;
goto error;
}
emu->irq = pci->irq;
/*
* Init to 0x02109204 :
* Clock accuracy = 0 (1000ppm)