On Mon, Nov 10, 2014 at 10:31:39PM +0100, Jean Delvare wrote: > There is a control bit in the PCI configuration space which disables > interrupts. If this bit is set, the driver should not try to make use > of interrupts, it won't receive any. > > Signed-off-by: Jean Delvare <[email protected]> > Cc: Wolfram Sang <[email protected]> > --- > drivers/i2c/busses/i2c-i801.c | 21 +++++++++++++++++++++ > 1 file changed, 21 insertions(+) > > --- linux-3.18-rc4.orig/drivers/i2c/busses/i2c-i801.c 2014-11-10 > 22:29:44.416991298 +0100 > +++ linux-3.18-rc4/drivers/i2c/busses/i2c-i801.c 2014-11-10 > 22:29:46.915045662 +0100 > @@ -110,12 +110,16 @@ > > /* PCI Address Constants */ > #define SMBBAR 4 > +#define SMBPCICTL 0x004 > #define SMBPCISTS 0x006 > #define SMBHSTCFG 0x040 > > /* Host status bits for SMBPCISTS */ > #define SMBPCISTS_INTS 0x08 > > +/* Control bits for SMBPCICTL */ > +#define SMBPCICTL_INTDIS 0x0400 > + > /* Host configuration bits for SMBHSTCFG */ > #define SMBHSTCFG_HST_EN 1 > #define SMBHSTCFG_SMB_SMI_EN 2 > @@ -1235,6 +1239,23 @@ static int i801_probe(struct pci_dev *de > priv->adapter.timeout = HZ / 5; > > if (priv->features & FEATURE_IRQ) { > + u16 pcictl, pcists; > + > + /* Complain if an interrupt is already pending */ > + pci_read_config_word(priv->pci_dev, SMBPCISTS, &pcists); > + if (pcists & SMBPCISTS_INTS) > + dev_warn(&dev->dev, "An interrupt is pending!\n");
You think it is better to not clear it?
> +
> + /* Check if interrupts have been disabled */
> + pci_read_config_word(priv->pci_dev, SMBPCICTL, &pcictl);
> + if (pcictl & SMBPCICTL_INTDIS) {
> + dev_warn(&dev->dev,
> + "Interrupts are disabled, will use polling\n");
I'd say it is more info than warning?
> + priv->features &= ~FEATURE_IRQ;
> + }
> + }
> +
> + if (priv->features & FEATURE_IRQ) {
> init_waitqueue_head(&priv->waitq);
>
> err = request_irq(dev->irq, i801_isr, IRQF_SHARED,
>
> --
> Jean Delvare
> SUSE L3 Support
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