From: "Yadi.hu" <yadi.hu@xxxxxxxxxxxxx> the driver executes request_irq() function before the base address of i2c registers is remapped in kernel space. If i2c controller shares an interrupt line with other devices,it is possible that an interrupt arrives immediately after request_irq() is called. Since the interrupt handler pch_i2c_handler() is active, it will read its own register to determine if this interrupt was from its own device. At this moment, base address of i2c registers is not remapped in kernel space yet,so the INT handler access a unknown address and a error occurs. Bad IO access at port 0x18 (return inl(port)) Call Trace: [<c102c733>] warn_slowpath_common+0x73/0xa0 [<c13109f5>] ? bad_io_access+0x45/0x50 [<c13109f5>] ? bad_io_access+0x45/0x50 [<c102c804>] warn_slowpath_fmt+0x34/0x40 [<c13109f5>] bad_io_access+0x45/0x50 [<c1310b62>] ioread32+0x22/0x40 [<c14c60db>] pch_i2c_handler+0x3b/0x120 [<c1092f34>] handle_irq_event_percpu+0x64/0x330 [<c109323b>] handle_irq_event+0x3b/0x60 [<c1095b50>] ? unmask_irq+0x30/0x30 [<c1095ba0>] handle_fasteoi_irq+0x50/0xe0 <IRQ> [<c16e7e78>] ? do_IRQ+0x48/0xc0 [<c16e7f6f>] ? smp_apic_timer_interrupt+0x7f/0x17a [<c16e7da9>] ? common_interrupt+0x29/0x30 [<c1008ebb>] ? mwait_idle+0x8b/0x2c0 [<c1009e8e>] ? cpu_idle+0x9e/0xc0 [<c16be408>] ? rest_init+0x6c/0x74 [<c19f770a>] ? start_kernel+0x311/0x318 [<c19f7231>] ? repair_env_string+0x51/0x51 [<c19f7078>] ? i386_start_kernel+0x78/0x7d ---[ end trace eb3a1028f468a140 ]--- i2c_eg20t 0000:05:0c.2: pch_i2c_handler :I2C-3 mode(0) is not supported Signed-off-by: Yadi.hu <yadi.hu@xxxxxxxxxxxxx> --- drivers/i2c/busses/i2c-eg20t.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/drivers/i2c/busses/i2c-eg20t.c b/drivers/i2c/busses/i2c-eg20t.c index 137125b..48483a5 100644 --- a/drivers/i2c/busses/i2c-eg20t.c +++ b/drivers/i2c/busses/i2c-eg20t.c @@ -773,13 +773,6 @@ static int pch_i2c_probe(struct pci_dev *pdev, /* Set the number of I2C channel instance */ adap_info->ch_num = id->driver_data; - ret = request_irq(pdev->irq, pch_i2c_handler, IRQF_SHARED, - KBUILD_MODNAME, adap_info); - if (ret) { - pch_pci_err(pdev, "request_irq FAILED\n"); - goto err_request_irq; - } - for (i = 0; i < adap_info->ch_num; i++) { pch_adap = &adap_info->pch_data[i].pch_adapter; adap_info->pch_i2c_suspended = false; @@ -808,16 +801,23 @@ static int pch_i2c_probe(struct pci_dev *pdev, } } + ret = request_irq(pdev->irq, pch_i2c_handler, IRQF_SHARED, + KBUILD_MODNAME, adap_info); + if (ret) { + pch_pci_err(pdev, "request_irq FAILED\n"); + goto err_request_irq; + } + pci_set_drvdata(pdev, adap_info); pch_pci_dbg(pdev, "returns %d.\n", ret); return 0; +err_request_irq: + pci_iounmap(pdev, base_addr); err_add_adapter: for (j = 0; j < i; j++) i2c_del_adapter(&adap_info->pch_data[j].pch_adapter); free_irq(pdev->irq, adap_info); -err_request_irq: - pci_iounmap(pdev, base_addr); err_pci_iomap: pci_release_regions(pdev); err_pci_req: -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html