From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Delvare Subject: [PATCH 3/4 v2] i2c-i801: Check if interrupts are disabled Date: Wed, 12 Nov 2014 10:25:37 +0100 Message-ID: <20141112102537.654bb894@endymion.delvare> References: <20141112101931.5f8c196a@endymion.delvare> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20141112101931.5f8c196a-R0o5gVi9kd7kN2dkZ6Wm7A@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Linux I2C Cc: Wolfram Sang List-Id: linux-i2c@vger.kernel.org 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 Cc: Wolfram Sang --- Changes since v1: * Turned warning message into info message and made it shorter. drivers/i2c/busses/i2c-i801.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) --- linux-3.18-rc4.orig/drivers/i2c/busses/i2c-i801.c 2014-11-11 14:56:35.777941563 +0100 +++ linux-3.18-rc4/drivers/i2c/busses/i2c-i801.c 2014-11-11 15:32:30.128418755 +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 +1239,22 @@ 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"); + + /* 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, -- Jean Delvare SUSE L3 Support