lkml.org 
[lkml]   [2015]   [May]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 3.19 081/177] ALSA: emu10k1: dont deadlock in proc-functions
    Date
    3.19-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Michael Gernoth <michael@gernoth.net>

    commit 91bf0c2dcb935a87e5c0795f5047456b965fd143 upstream.

    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>
    Signed-off-by: Takashi Iwai <tiwai@suse.de>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    sound/pci/emu10k1/emuproc.c | 12 ------------
    1 file changed, 12 deletions(-)

    --- a/sound/pci/emu10k1/emuproc.c
    +++ b/sound/pci/emu10k1/emuproc.c
    @@ -241,31 +241,22 @@ static void snd_emu10k1_proc_spdif_read(
    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_rea
    {
    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);
    }
    }



    \
     
     \ /
      Last update: 2015-05-02 22:01    [W:4.042 / U:0.060 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site