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    Subject[121/140] ALSA: Echoaudio, fix Guru Meditation #00000005.48454C50
    2.6.33-stable review patch.  If anyone has any objections, please let us know.

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

    From: Giuliano Pochini <pochini@shiny.it>

    commit b721e68bdc5b39c51bf6a1469f8d3663fbe03243 upstream.

    This patch fixes a division by zero error in the irq handler.

    There is a small window between the hw_params() callback and when
    runtime->frame_bits is set by ALSA middle layer. When another substream is
    already running, if an interrupt is delivered during that window the irq
    handler calls pcm_pointer() which does a division by zero. The patch below
    makes the irq handler skip substreams that are initialized but not started
    yet. Cc to Clemens Ladisch because he proposed an alternate fix.

    For more information, please read the original thread in the linux-kernel
    mailing list: http://lkml.org/lkml/2010/2/2/187

    Signed-off-by: Giuliano Pochini <pochini@shiny.it>
    Signed-off-by: Takashi Iwai <tiwai@suse.de>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

    ---
    sound/pci/echoaudio/echoaudio.c | 4 +++-
    1 file changed, 3 insertions(+), 1 deletion(-)

    --- a/sound/pci/echoaudio/echoaudio.c
    +++ b/sound/pci/echoaudio/echoaudio.c
    @@ -1821,7 +1821,9 @@ static irqreturn_t snd_echo_interrupt(in
    /* The hardware doesn't tell us which substream caused the irq,
    thus we have to check all running substreams. */
    for (ss = 0; ss < DSP_MAXPIPES; ss++) {
    - if ((substream = chip->substream[ss])) {
    + substream = chip->substream[ss];
    + if (substream && ((struct audiopipe *)substream->runtime->
    + private_data)->state == PIPE_STATE_STARTED) {
    period = pcm_pointer(substream) /
    substream->runtime->period_size;
    if (period != chip->last_period[ss]) {



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