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>
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