2.4.18 drivers/sound/maestro.c

Hi !

maestro.c:3537 takes care about volume button pressing when requesting irq (maestro_probe) :

	if((ret=request_irq(card->irq, ess_interrupt, SA_SHIRQ, card_names[card_type], card)))
	{
		<snipped>
	}

	/* Turn on hardware volume control interrupt.
	   This has to come after we grab the IRQ above,
	   or a crash will result on installation if a button has been pressed,
	   because in that case we'll get an immediate interrupt. */
	n = inw(iobase+0x18);
	n|=(1<<6);
	outw(n, iobase+0x18);

but not when unloading module : in fact, this bit is never cleared. Indeed, loading the module, unloading it, and pressing a volume button immediately crashes.

This cures the problem :

diff -urN linux-2.4.18/drivers/sound/maestro.c linux-2.4.18-cor/drivers/sound/maestro.c
@@ -3569,9 +3569,18 @@
 static void maestro_remove(struct pci_dev *pcidev) {
 	struct ess_card *card = pci_get_drvdata(pcidev);
 	int i;
+	u32 n;
 
 	/* XXX maybe should force stop bob, but should be all
 		stopped by _release by now */
+
+	/* Turn off hardware volume control interrupt.
+	   This has to come before we leave the IRQ below,
+	   or a crash results if a button is pressed ! */
+	n = inw(card->iobase+0x18);
+	n&=~(1<<6);
+	outw(n, card->iobase+0x18);
+
 	free_irq(card->irq, card);
 	unregister_sound_mixer(card->dev_mixer);
 	for(i=0;i<NR_DSPS;i++)

This patch also apply to 2.5 series (tested on 2.5.24) in linux/sound/oss by using -p3.

Best regards,

Samuel Thibault