From fb47423dc7bf43301048d77289ce0114959de4de Mon Sep 17 00:00:00 2001 From: Praveen Talari Date: Thu, 8 Jan 2026 09:40:06 +0530 Subject: serial: qcom_geni: Fix BT failure regression on RB2 platform Commit 10904d725f6e ("serial: qcom-geni: Enable PM runtime for serial driver") caused BT init to fail during bootup on the RB2 platform, preventing proper BT initialization. However, BT works correctly after bootup completes. The issue occurs when runtime PM is enabled and uart_add_one_port() is called before wakeup IRQ setup. The uart_add_one_port() call activates the device through runtime PM, which configures GPIOs to the "qup_x" pinmux function during runtime resume. When wakeup IRQ registration happens afterward using dev_pm_set_dedicated_wake_irq(), these GPIOs are reset back to the "gpio" pinmux function, which impacts the RX GPIO and leads to Bluetooth failures. Fix this by ensuring wakeup IRQ setup is completed before calling uart_add_one_port() to prevent the pinmux function conflict. Fixes: 10904d725f6e ("serial: qcom-geni: Enable PM runtime for serial driver") Reported-by: Dmitry Baryshkov Closes: https://lore.kernel.org/all/20251110101043.2108414-4-praveen.talari@oss.qualcomm.com/ Tested-by: Dmitry Baryshkov Reviewed-by: Dmitry Baryshkov Signed-off-by: Praveen Talari Link: https://patch.msgid.link/20260108041006.1874757-1-praveen.talari@oss.qualcomm.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/qcom_geni_serial.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) (limited to 'drivers/tty') diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index 6ce6528f5c10..e6b0a55f0cfb 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -1888,12 +1888,6 @@ static int qcom_geni_serial_probe(struct platform_device *pdev) if (ret) goto error; - devm_pm_runtime_enable(port->se.dev); - - ret = uart_add_one_port(drv, uport); - if (ret) - goto error; - if (port->wakeup_irq > 0) { device_init_wakeup(&pdev->dev, true); ret = dev_pm_set_dedicated_wake_irq(&pdev->dev, @@ -1901,11 +1895,16 @@ static int qcom_geni_serial_probe(struct platform_device *pdev) if (ret) { device_init_wakeup(&pdev->dev, false); ida_free(&port_ida, uport->line); - uart_remove_one_port(drv, uport); goto error; } } + devm_pm_runtime_enable(port->se.dev); + + ret = uart_add_one_port(drv, uport); + if (ret) + goto error; + return 0; error: -- cgit v1.2.3 From 27aff0a56b3c77ea1a73641c9b3c4172a8f7238f Mon Sep 17 00:00:00 2001 From: Marnix Rijnart Date: Mon, 12 Jan 2026 01:08:23 +0100 Subject: serial: 8250_pci: Fix broken RS485 for F81504/508/512 Fintek F81504/508/512 can support both RTS_ON_SEND and RTS_AFTER_SEND, but pci_fintek_rs485_supported only announces the former. This makes it impossible to unset SER_RS485_RTS_ON_SEND from userspace because of uart_sanitize_serial_rs485(). Some devices with these chips need RTS low on TX, so they are effectively broken. Fix this by announcing the support for SER_RS485_RTS_AFTER_SEND, similar to commit 068d35a7be65 ("serial: sc16is7xx: announce support for SER_RS485_RTS_ON_SEND"). Fixes: 4afeced55baa ("serial: core: fix sanitizing check for RTS settings") Cc: stable Signed-off-by: Marnix Rijnart Link: https://patch.msgid.link/20260112000931.61703-1-marnix.rijnart@iwell.eu Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_pci.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/tty') diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c index c5a932f48f74..3efe075ef7b2 100644 --- a/drivers/tty/serial/8250/8250_pci.c +++ b/drivers/tty/serial/8250/8250_pci.c @@ -1658,7 +1658,7 @@ static int pci_fintek_rs485_config(struct uart_port *port, struct ktermios *term } static const struct serial_rs485 pci_fintek_rs485_supported = { - .flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND, + .flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND, /* F81504/508/512 does not support RTS delay before or after send */ }; -- cgit v1.2.3 From 32f37e57583f869140cff445feedeea8a5fea986 Mon Sep 17 00:00:00 2001 From: Krzysztof Kozlowski Date: Fri, 23 Jan 2026 08:21:40 +0100 Subject: serial: Fix not set tty->port race condition Revert commit bfc467db60b7 ("serial: remove redundant tty_port_link_device()") because the tty_port_link_device() is not redundant: the tty->port has to be confured before we call uart_configure_port(), otherwise user-space can open console without TTY linked to the driver. This tty_port_link_device() was added explicitly to avoid this exact issue in commit fb2b90014d78 ("tty: link tty and port before configuring it as console"), so offending commit basically reverted the fix saying it is redundant without addressing the actual race condition presented there. Reproducible always as tty->port warning on Qualcomm SoC with most of devices disabled, so with very fast boot, and one serial device being the console: printk: legacy console [ttyMSM0] enabled printk: legacy console [ttyMSM0] enabled printk: legacy bootconsole [qcom_geni0] disabled printk: legacy bootconsole [qcom_geni0] disabled ------------[ cut here ]------------ tty_init_dev: ttyMSM driver does not set tty->port. This would crash the kernel. Fix the driver! WARNING: drivers/tty/tty_io.c:1414 at tty_init_dev.part.0+0x228/0x25c, CPU#2: systemd/1 Modules linked in: socinfo tcsrcc_eliza gcc_eliza sm3_ce fuse ipv6 CPU: 2 UID: 0 PID: 1 Comm: systemd Tainted: G S 6.19.0-rc4-next-20260108-00024-g2202f4d30aa8 #73 PREEMPT Tainted: [S]=CPU_OUT_OF_SPEC Hardware name: Qualcomm Technologies, Inc. Eliza (DT) ... tty_init_dev.part.0 (drivers/tty/tty_io.c:1414 (discriminator 11)) (P) tty_open (arch/arm64/include/asm/atomic_ll_sc.h:95 (discriminator 3) drivers/tty/tty_io.c:2073 (discriminator 3) drivers/tty/tty_io.c:2120 (discriminator 3)) chrdev_open (fs/char_dev.c:411) do_dentry_open (fs/open.c:962) vfs_open (fs/open.c:1094) do_open (fs/namei.c:4634) path_openat (fs/namei.c:4793) do_filp_open (fs/namei.c:4820) do_sys_openat2 (fs/open.c:1391 (discriminator 3)) ... Starting Network Name Resolution... Apparently the flow with this small Yocto-based ramdisk user-space is: driver (qcom_geni_serial.c): user-space: ============================ =========== qcom_geni_serial_probe() uart_add_one_port() serial_core_register_port() serial_core_add_one_port() uart_configure_port() register_console() | | open console | ... | tty_init_dev() | driver->ports[idx] is NULL | tty_port_register_device_attr_serdev() tty_port_link_device() <- set driver->ports[idx] Fixes: bfc467db60b7 ("serial: remove redundant tty_port_link_device()") Cc: stable@vger.kernel.org Signed-off-by: Krzysztof Kozlowski Reviewed-by: Jiri Slaby Link: https://patch.msgid.link/20260123072139.53293-2-krzysztof.kozlowski@oss.qualcomm.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/serial_core.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'drivers/tty') diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 9930023e924c..2805cad10511 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -3074,6 +3074,12 @@ static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *u if (uport->cons && uport->dev) of_console_check(uport->dev->of_node, uport->cons->name, uport->line); + /* + * TTY port has to be linked with the driver before register_console() + * in uart_configure_port(), because user-space could open the console + * immediately after. + */ + tty_port_link_device(port, drv->tty_driver, uport->line); uart_configure_port(drv, state, uport); port->console = uart_console(uport); -- cgit v1.2.3