From c17c4059df2471183a0e0d567677cbd7f0e0a980 Mon Sep 17 00:00:00 2001 From: Jonathan Lemon Date: Wed, 9 Mar 2022 14:34:27 -0800 Subject: ptp: ocp: add UPF_NO_THRE_TEST flag for serial ports The serial port driver attempts to test for correct THRE behavior on startup. However, it does this by disabling interrupts, and then intentionally trying to trigger an interrupt in order to see if the IIR bit is set in the UART. However, in this FPGA design, the UART interrupt is generated through the MSI vector, so when interrupts are re-enabled after the test, the DMAR-IR reports an unhandled IRTE entry, since no irq handler is installed at this point - it is installed after the test. This only happens on the /second/ open of the UART, since on the first open, the x86_vector has installed and activated by the driver probe, and is correctly handled. When the serial port is closed for the first time, this vector is deactivated and removed, leading to this error. Signed-off-by: Jonathan Lemon Link: https://lore.kernel.org/r/20220309223427.34745-1-jonathan.lemon@gmail.com Signed-off-by: Jakub Kicinski --- drivers/ptp/ptp_ocp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/ptp') diff --git a/drivers/ptp/ptp_ocp.c b/drivers/ptp/ptp_ocp.c index 98b3f01e76c9..653286e01b90 100644 --- a/drivers/ptp/ptp_ocp.c +++ b/drivers/ptp/ptp_ocp.c @@ -1410,7 +1410,7 @@ ptp_ocp_serial_line(struct ptp_ocp *bp, struct ocp_resource *r) uart.port.mapbase = pci_resource_start(pdev, 0) + r->offset; uart.port.irq = pci_irq_vector(pdev, r->irq_vec); uart.port.uartclk = 50000000; - uart.port.flags = UPF_FIXED_TYPE | UPF_IOREMAP; + uart.port.flags = UPF_FIXED_TYPE | UPF_IOREMAP | UPF_NO_THRE_TEST; uart.port.type = PORT_16550A; return serial8250_register_8250_port(&uart); -- cgit v1.2.3