OSS trident: fix locking around write_voice_regs (3b20b9b4) · Commits · 戴 / test

trident_write_voice_regs() was getting called with the card spinlock held in only some cases. Fix it. Explanation: we allocate a new virtual channel in open, and then we frob some hardware registers (in write_voice_regs) for that channel. But the hardware registers are shared with other channels, which may be trying to frob the some registers (albeit for another channel) via ioctl(SNDCTL_DSP_SPEED). Fixed bugzilla.kernel.org bug #8172 (http://bugme.osdl.org/show_bug.cgi?id=8172 ) Signed-off-by:

Muli Ben-Yehuda <muli@il.ibm.com> Cc: <tammy000@gmail.com> Cc: <bunk@stusta.de> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

sound/oss/trident.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -2702,6 +2702,7 @@ trident_open(struct inode inode, struct file file)
		struct trident_card *card = devs;
		struct trident_state *state = NULL;
		struct dmabuf *dmabuf = NULL;
		unsigned long flags;

		/* Added by Matt Wu 01-05-2001 */
		/* TODO: there's some redundacy here wrt the check below */
		@@ -2779,7 +2780,9 @@ trident_open(struct inode inode, struct file file)
		/* set default channel attribute to normal playback */
		dmabuf->channel->attribute = CHANNEL_PB;
		}
		spin_lock_irqsave(&card->lock, flags);
		trident_set_dac_rate(state, 8000);
		spin_unlock_irqrestore(&card->lock, flags);
		}

		if (file->f_mode & FMODE_READ) {
		@@ -2797,7 +2800,9 @@ trident_open(struct inode inode, struct file file)
		dmabuf->channel->attribute = (CHANNEL_REC \| PCM_LR \|
		MONO_MIX);
		}
		spin_lock_irqsave(&card->lock, flags);
		trident_set_adc_rate(state, 8000);
		spin_unlock_irqrestore(&card->lock, flags);

		/* Added by Matt Wu 01-05-2001 */
		if (card->pci_id == PCI_DEVICE_ID_ALI_5451)

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