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ALSA: emu10k1: don't deadlock in proc-functions 

The functions snd_emu10k1_proc_spdif_read and snd_emu1010_fpga_read
acquire the emu_lock before accessing the FPGA. The function used
to access the FPGA (snd_emu1010_fpga_read) also tries to take
the emu_lock which causes a deadlock.
Remove the outer locking in the proc-functions (guarding only the
already safe fpga read) to prevent this deadlock.

[removed superfluous flags variables too -- tiwai]

Signed-off-by: Michael Gernoth <michael@gernoth.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Michael Gernoth 2015-04-09 23:42:15 +02:00 committed by Takashi Iwai
parent 3dc8523fa7
commit 91bf0c2dcb
1 changed files with 0 additions and 12 deletions
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12
sound/pci/emu10k1/emuproc.c
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@ -241,31 +241,22 @@ static void snd_emu10k1_proc_spdif_read(struct snd_info_entry *entry,
struct snd_emu10k1 *emu = entry->private_data;
u32 value;
u32 value2;
unsigned long flags;
u32 rate;
if (emu->card_capabilities->emu_model) {
spin_lock_irqsave(&emu->emu_lock, flags);
snd_emu1010_fpga_read(emu, 0x38, &value);
spin_unlock_irqrestore(&emu->emu_lock, flags);
if ((value & 0x1) == 0) {
spin_lock_irqsave(&emu->emu_lock, flags);
snd_emu1010_fpga_read(emu, 0x2a, &value);
snd_emu1010_fpga_read(emu, 0x2b, &value2);
spin_unlock_irqrestore(&emu->emu_lock, flags);
rate = 0x1770000 / (((value << 5) | value2)+1);
snd_iprintf(buffer, "ADAT Locked : %u\n", rate);
} else {
snd_iprintf(buffer, "ADAT Unlocked\n");
}
spin_lock_irqsave(&emu->emu_lock, flags);
snd_emu1010_fpga_read(emu, 0x20, &value);
spin_unlock_irqrestore(&emu->emu_lock, flags);
if ((value & 0x4) == 0) {
spin_lock_irqsave(&emu->emu_lock, flags);
snd_emu1010_fpga_read(emu, 0x28, &value);
snd_emu1010_fpga_read(emu, 0x29, &value2);
spin_unlock_irqrestore(&emu->emu_lock, flags);
rate = 0x1770000 / (((value << 5) | value2)+1);
snd_iprintf(buffer, "SPDIF Locked : %d\n", rate);
} else {
@ -410,14 +401,11 @@ static void snd_emu_proc_emu1010_reg_read(struct snd_info_entry *entry,
{
struct snd_emu10k1 *emu = entry->private_data;
u32 value;
unsigned long flags;
int i;
snd_iprintf(buffer, "EMU1010 Registers:\n\n");
for(i = 0; i < 0x40; i+=1) {
spin_lock_irqsave(&emu->emu_lock, flags);
snd_emu1010_fpga_read(emu, i, &value);
spin_unlock_irqrestore(&emu->emu_lock, flags);
snd_iprintf(buffer, "%02X: %08X, %02X\n", i, value, (value >> 8) & 0x7f);
}
}