laptop-kernel/drivers/tty/serial/8250, branch master

Merge tag 'printk-for-7.3-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux

2026-10-06T09:32:54Z

Pull printk fix from Petr Mladek: - Allow using Braille console with a serial console driver converted to NBCON API * tag 'printk-for-7.3-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: braille: nbcon: Allow to use a serial console with NBCON API as Braille console

braille: nbcon: Allow to use a serial console with NBCON API as Braille console

2026-10-02T08:26:42Z

The Braille console is not registered in console_list. Instead, it is integrated with the virtual terminal (VT) and shows what is displayed on the terminal. It writes the data using con->write*() callback of the associated serial console driver. braille_write() is called from the VT code under console_lock(). The associated serial console driver can be converted to the NBCON API though. The situation is similar to flushing nbcon consoles in the legacy loop when some boot consoles are still registered, see nbcon_legacy_emit_next_record(). But there is a big difference though. braille_write() is not directly called from the code paths flushing registered consoles. The VT code expects that braille_write() succeeds. It does not replay the message when it can't acquire the ownership. As a result, braille_write(): + must try harder to get the ownership. + has to be synchronized only against non-printk serial console which depend nbcon_device_try_acquire() using NBCON_PRIO_NORMAL. Let's look at it from another side and try to simulate the original locking using the NBCON API: 1. Take con->device_lock(), aka the port->lock in the legacy serial console driver. 2. Acquire nbcon context to provide some synchronization for a panic() context. Use NBCON_PRIO_NORMAL because it contends only with nbcon_device_try_acquire() users. Do it in a busy loop. It should always succeed when con->device_lock() succeeded because all other users do the same. The only exception is when the context get acquired by a CPU handling panic. 3. In panic, disable interrupts and try to acquire the nbcon context. Use NBCON_PRIO_PANIC. And try even an unsafe takeover because otherwise the Braille console won't see the text shown during panic(). It is similar to the oops_in_progress/trylock handling in the legacy serial console driver. Finally, avoid the newline prepending logic in the existing serial console drivers when they are used as a Braille console. As explained above, the Braille console shows the last modified line on the terminal (VT). braille_write() is called when single characters are added. Most messages are not ended by newline. Anyway, the VT code does not have logic to reply partially printed messages. Fixes: 13189fa73afa ("printk: nbcon: Rely on kthreads for normal operation") Reviewed-by: John Ogness [pmladek@suse.com: Remove white space changes in braille_register_console(). Typo fix.] Link: https://patch.msgid.link/20261001140727.124398-2-pmladek@suse.com Signed-off-by: Petr Mladek

serial: 8250_bcm7271: fix use-after-free in brcmuart_remove()

2026-09-23T10:22:08Z

brcmuart_handle_irq() starts priv->hrt to work around a receive-timeout quirk of the 8250 core when hardware flow control is enabled; the timer callback brcmuart_hrtimer_func() dereferences priv. brcmuart_remove() cancels the hrtimer before it unregisters the port, so a receive-timeout interrupt that arrives in between re-arms the timer. After devm frees priv, the callback runs on freed memory. Unregister the port before cancelling the hrtimer. serial8250_unregister_port() shuts the port down and frees its IRQ, so brcmuart_handle_irq() can no longer restart the timer, and the final hrtimer_cancel() drains any timer that was armed before or during the unregister. This issue was found by an in-house static analysis tool. Fixes: 41a469482de2 ("serial: 8250: Add new 8250-core based Broadcom STB driver") Cc: stable@kernel.org Assisted-by: Codex:gpt-5.6 Co-developed-by: Song Li Signed-off-by: Song Li Signed-off-by: Fan Wu Reviewed-by: Florian Fainelli Link: https://patch.msgid.link/20260909084002.686911-1-fanwu01@zju.edu.cn Signed-off-by: Greg Kroah-Hartman

serial: 8250_omap: fix wake irq cleared during suspend

2026-09-23T10:20:40Z

The wake irq was cleared in shutdown(), which runs during the suspend sequence, making it impossible to wake the system via UART. Move wake irq setup to probe() and teardown to remove() so the irq remains armed during suspend when the UART is a wakeup source. Cc: stable@kernel.org Fixes: 61929cf0169d ("tty: serial: Add 8250-core based omap driver") Signed-off-by: Kendall Willis Reviewed-by: Tony Lindgren Link: https://patch.msgid.link/20260825-uart-wakeirq-fix-v2-1-0b9fba03d9b6@ti.com Signed-off-by: Greg Kroah-Hartman

serial: 8250: Change console_msr_work to IRQ_WORK_LAZY

2026-09-22T08:34:42Z

Change console_msr_work (defers MSR handling) to be IRQ_WORK_LAZY, thus not raising an IRQ upon irq_work queueing. The irq_work is then handled on the next kernel tick. This additional delay is acceptable because any pending MSR handling is also performed in the interrupt handler, if mctrl is queried, and during console resume. Using IRQ_WORK_LAZY has the benefit of not needing to raise an IRQ for each line of atomic console printing when modem control is active. On a side note, the Tegra20 and Tegra30 platforms can hang if an irq_work IRQ is raised while entering cpuidle states. This problem was reproducible by performing atomic printing while entering cpuidle. So this change also provides a workaround for these platforms (as long as they are not running tickless). The discussion on this topic is linked below. Link: https://lore.kernel.org/lkml/f3757a75-0ba1-4558-bf57-f19ab7e59a4c@nvidia.com Fixes: d3539347022a ("serial: 8250: Switch to nbcon console, take 2") Signed-off-by: John Ogness Reviewed-by: Petr Mladek Tested-by: Jon Hunter Link: https://patch.msgid.link/20260921143939.170314-1-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman

Merge tag 'tty-7.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2026-08-25T17:59:12Z

Pull TTY / serial driver updates from Greg KH: "Here is the "big" set of tty and serial driver updates for 7.3-rc1. Not really all that much happened this development cycle for this subsystem, changes in here are: - removal of the ipwireless driver as it's no longer used or needed - new 8250_mxpcie driver added - qcom serial driver updates and additions - vt mode validation addition - lots of other small serial driver updates and additions All of these have been in linux-next for weeks with no reported issues" * tag 'tty-7.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (97 commits) serial: imx: serialize imx_uart_ports[] lifetime tty: clear cdev pointer after cdev_add() failure tty: skip cdev_del() when no cdev is registered serial: core: clear freed pointers on uart_register_driver() failure serial: core: do fallible allocations before the console can be registered serial: 8250_mxpcie: implement rx_trig_bytes callbacks via MUEx50 RTL serial: 8250_mxpcie: introduce per-port private data structure serial: 8250: allow UART drivers to override rx_trig_bytes handling serial: 8250_mxpcie: add break support for RS485 using MUEx50 features serial: 8250: allow low-level drivers to override break control serial: 8250_mxpcie: support serial interface mode switching serial: 8250_mxpcie: speed up TX using memory-mapped FIFO window serial: 8250_mxpcie: speed up RX using memory-mapped FIFO window serial: 8250_mxpcie: add custom handle_irq callback serial: 8250_mxpcie: offload XON/XOFF flow control to MUEx50 hardware serial: 8250_mxpcie: enable automatic RTS/CTS flow control serial: 8250_mxpcie: enable enhanced mode and program FIFO trigger levels serial: 8250: add Moxa MUEx50 UART port type serial: 8250: split Moxa PCIe serial board support out of 8250_pci serial: qcom-geni: Use geni_se_set_perf_level() for baud rate perf level ...

serial: 8250_mxpcie: implement rx_trig_bytes callbacks via MUEx50 RTL

2026-08-03T14:51:58Z

The MUEx50 UART exposes a programmable RX trigger level via the RTL register. Implement uart_port RX trigger set/get callbacks for the mxpcie driver and wire them up to the generic rx_trig_bytes sysfs interface. Store the configured trigger level in the per-port private data. Signed-off-by: Crescent Hsieh Link: https://patch.msgid.link/20260731074820.735619-15-crescentcy.hsieh@moxa.com Signed-off-by: Greg Kroah-Hartman

serial: 8250_mxpcie: introduce per-port private data structure

2026-08-03T14:51:57Z

Introduce a private per-port data structure for the mxpcie driver and replace the shared flexible array of registered lines with an array of per-port objects. This prepares the driver for storing per-port state needed by subsequent features. No functional change intended. Signed-off-by: Crescent Hsieh Link: https://patch.msgid.link/20260731074820.735619-14-crescentcy.hsieh@moxa.com Signed-off-by: Greg Kroah-Hartman

serial: 8250: allow UART drivers to override rx_trig_bytes handling

2026-08-03T14:51:57Z

The rx_trig_bytes sysfs attribute currently relies on 8250-internal helper functions and assumes a fixed mapping between trigger levels and FIFO behavior. Some UARTs provide hardware-specific RX trigger mechanisms that do not fit this model. Add optional uart_port callbacks for setting and getting the RX trigger level, and use them when provided, while preserving the existing 8250 helpers as the default fallback. Signed-off-by: Crescent Hsieh Link: https://patch.msgid.link/20260731074820.735619-13-crescentcy.hsieh@moxa.com Signed-off-by: Greg Kroah-Hartman

serial: 8250_mxpcie: add break support for RS485 using MUEx50 features

2026-08-03T14:51:57Z

On MUEx50, break signaling under RS485 requires a driver-specific sequence and cannot be handled correctly by the generic 8250 break implementation alone. Implement a mxpcie break_ctl callback that performs MUEx50-specific break handling when RS485 is enabled and fall back to the default 8250 break handling for other modes. Signed-off-by: Crescent Hsieh Link: https://patch.msgid.link/20260731074820.735619-12-crescentcy.hsieh@moxa.com Signed-off-by: Greg Kroah-Hartman