Le Thursday 03 March 2016 à 21:57 +0100, Wolfram Sang a écrit :
> On Tue, Jan 19, 2016 at 11:00:48AM -0600, minyard@xxxxxxx wrote:
> > From: Corey Minyard <cminyard@xxxxxxxxxx>
> >
> > Getting the same alert twice in a row is legal and normal,
> > especially on a fast device (like running in qemu). Kind of
> > like interrupts. So don't report duplicate alerts, and deliver
> > them normally.
> >
> > Signed-off-by: Corey Minyard <cminyard@xxxxxxxxxx>
>
> Looks plausible to me, but I never used SMBALERT myself. Any chance this
> can cause a regression? Jean, what do you think?
I'm afraid I had a good reason to add this check back then. I'll test
with my ADM1032 evaluation board when I get back home (tomorrow at the
earliest.) Maybe my hardware was misbehaving, in which case I agree any
filtering should be done at the device driver level. But I must double
check what the SMBus specification says too.
Either way the patch's subject is misleading. Should be "Don't filter
out duplicate alerts" or something like that.
> > ---
> > drivers/i2c/i2c-smbus.c | 7 -------
> > 1 file changed, 7 deletions(-)
> >
> > diff --git a/drivers/i2c/i2c-smbus.c b/drivers/i2c/i2c-smbus.c
> > index 94765a8..cecd423 100644
> > --- a/drivers/i2c/i2c-smbus.c
> > +++ b/drivers/i2c/i2c-smbus.c
> > @@ -75,7 +75,6 @@ static void smbus_alert(struct work_struct *work)
> > {
> > struct i2c_smbus_alert *alert;
> > struct i2c_client *ara;
> > - unsigned short prev_addr = 0; /* Not a valid address */
> >
> > alert = container_of(work, struct i2c_smbus_alert, alert);
> > ara = alert->ara;
> > @@ -99,18 +98,12 @@ static void smbus_alert(struct work_struct *work)
> > data.flag = status & 1;
> > data.addr = status >> 1;
> >
> > - if (data.addr == prev_addr) {
> > - dev_warn(&ara->dev, "Duplicate SMBALERT# from dev "
> > - "0x%02x, skipping\n", data.addr);
> > - break;
> > - }
> > dev_dbg(&ara->dev, "SMBALERT# from dev 0x%02x, flag %d\n",
> > data.addr, data.flag);
> >
> > /* Notify driver for the device which issued the alert */
> > device_for_each_child(&ara->adapter->dev, &data,
> > smbus_do_alert);
> > - prev_addr = data.addr;
> > }
> >
> > /* We handled all alerts; re-enable level-triggered IRQs */
--
Jean Delvare
SUSE L3 Support
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