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    SubjectRe: [PATCH 2/3 v2] i2c: i801: enable irq for i801 smbus transactions
    On Wed, Jun 20, 2012 at 4:58 PM, Jean Delvare <khali@linux-fr.org> wrote:
    > On Tue, 19 Jun 2012 20:47:04 +0200, Jean Delvare wrote:
    >> On Fri,  6 Jan 2012 18:58:21 +0800, Daniel Kurtz wrote:
    >> > @@ -879,8 +953,24 @@ static int __devinit i801_probe(struct pci_dev *dev,
    >> >     i801_probe_optional_slaves(priv);
    >> >
    >> >     pci_set_drvdata(dev, priv);
    >> > +
    >> > +   if (priv->features & FEATURE_IRQ) {
    >> > +           init_waitqueue_head(&priv->waitq);
    >> > +           spin_lock_init(&priv->lock);
    >> > +
    >> > +           err = request_irq(dev->irq, i801_isr, IRQF_SHARED,
    >> > +                             i801_driver.name, priv);
    >> > +           if (err) {
    >> > +                   dev_err(&dev->dev, "Failed to allocate irq %d: %d",
    >>
    >> Missing "\n".
    >>
    >> > +                           dev->irq, err);
    >> > +                   goto exit_del_adapter;
    >> > +           }
    >>
    >> I believe order is wrong, and interrupt handler should be installed
    >> _before_ registering the adapter. Otherwise you have a race condition
    >> where the handler could be called before the waitqueue and spinlock are
    >> initialized.
    >
    > Oh, and it's not a theoretical thing. I can reproducibly crash the
    > kernel by removing and loading the i2c-i801 driver again. Swapping
    > request_irq() and i2c_add_adapter() solves it.

    Jean,

    Thanks for taking a look at these patches... and for testing them!
    They were from more than 7 months ago, so it will take me a little
    time to context switch back to the point where I can really digest
    your feedback and update and test them again myself. But, I wanted to
    just let you know that I am reading your review comments, and will get
    to it as soon as I can.
    Speaking of which, I have only seen comments on patches 1 & 2 so far.
    Any comments on patch 3?

    -Daniel

    >
    > --
    > Jean Delvare
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