On some systems IRQ lines might be shared between multiple devices. If so, the irqflags have to be configured accordingly. The reason is: The 8250 port startup code performs IRQ tests *before* the IRQ handler for that particular port is registered. This commit fixed the below issue: [ 973.782131] 8250 request irq 00000000f5a0e2ae 00000000f5a0e2ae 0 [ 973.785414] genirq: Flags mismatch irq 16. 00000004 (ttyS0) vs. 00000084 (ipmi_si) [ 973.788741] CPU: 0 PID: 1 Comm: systemd Tainted: G E 4.19.0-1.0.0.1.rc2 #5 [ 973.792112] Hardware name: Huawei TaiShan 2280 V2/BC82AMDDA, BIOS 0.18 06/10/2019 [ 973.795577] Call trace: [ 973.799018] dump_backtrace+0x0/0x198 [ 973.802493] show_stack+0x24/0x30 [ 973.805965] dump_stack+0x9c/0xbc [ 973.809357] __setup_irq+0x150/0x6c0 [ 973.812663] request_threaded_irq+0xe8/0x180 [ 973.815891] univ8250_setup_irq+0x278/0x2a0 [ 973.819007] serial8250_do_startup+0x468/0x818 [ 973.822060] serial8250_startup+0x38/0x48 [ 973.825099] uart_startup.part.9+0x11c/0x270 [ 973.828156] uart_port_activate+0x64/0x98 [ 973.831247] tty_port_open+0xac/0x110 [ 973.834349] uart_open+0x2c/0x40 [ 973.837415] tty_open+0x110/0x3f8 [ 973.840464] chrdev_open+0xc8/0x248 [ 973.843584] do_dentry_open+0x118/0x358 [ 973.846615] vfs_open+0x38/0x48 [ 973.849621] do_last+0x23c/0x808 [ 973.852610] path_openat+0x88/0x260 [ 973.855596] do_filp_open+0x88/0x100 [ 973.858582] do_sys_open+0x188/0x218 [ 973.861564] __arm64_sys_openat+0x2c/0x38 [ 973.864575] el0_svc_common+0xac/0x178 [ 973.867592] el0_svc_handler+0x38/0x78 [ 973.870570] el0_svc+0x8/0xc Signed-off-by: Li RongQing <lirongqing@xxxxxxxxx> --- drivers/tty/serial/8250/8250_pnp.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/tty/serial/8250/8250_pnp.c b/drivers/tty/serial/8250/8250_pnp.c index de90d681b64c..10c260928952 100644 --- a/drivers/tty/serial/8250/8250_pnp.c +++ b/drivers/tty/serial/8250/8250_pnp.c @@ -476,6 +476,7 @@ serial_pnp_probe(struct pnp_dev *dev, const struct pnp_device_id *dev_id) uart.port.flags |= UPF_SHARE_IRQ; uart.port.uartclk = 1843200; uart.port.dev = &dev->dev; + uart.port.irqflags |= IRQF_SHARED; line = serial8250_register_8250_port(&uart); if (line < 0 || (flags & CIR_PORT)) -- 2.16.2
