i2c: i801: Check if interrupts are disabled
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 <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index a6f3bc3..3f1f303 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -109,12 +109,16 @@
/* 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
@@ -1232,6 +1236,22 @@
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");
+
+ /* Check if interrupts have been disabled */
+ pci_read_config_word(priv->pci_dev, SMBPCICTL, &pcictl);
+ if (pcictl & SMBPCICTL_INTDIS) {
+ dev_info(&dev->dev, "Interrupts are disabled\n");
+ priv->features &= ~FEATURE_IRQ;
+ }
+ }
+
+ if (priv->features & FEATURE_IRQ) {
init_waitqueue_head(&priv->waitq);
err = request_irq(dev->irq, i801_isr, IRQF_SHARED,