kernel/drivers/tty, branch linux-6.18.y

serial: 8250: 8250_omap.c: Clear DMA RX running status only after DMA termination is done

2026-03-04T12:20:35Z

[ Upstream commit a5fd8945a478ff9be14812693891d7c9b4185a50 ] Clear rx_running flag only after DMA teardown polling completes. In the previous implementation the flag was being cleared while hardware teardown was still in progress, creating a mismatch between software state (flag = 0, "ready") and hardware state (still terminating). Signed-off-by: Moteen Shah Link: https://patch.msgid.link/20260112081829.63049-3-m-shah@ti.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

serial: 8250: 8250_omap.c: Add support for handling UART error conditions

2026-03-04T12:20:35Z

[ Upstream commit 623b07b370e9963122d167e04fdc1dc713ebfbaf ] The DMA IRQ handler does not accounts for the overrun(OE) or any other errors being reported by the IP before triggering a DMA transaction which leads to the interrupts not being handled resulting into an IRQ storm. The way to handle OE is to: 1. Reset the RX FIFO. 2. Read the UART_RESUME register, which clears the internal flag Earlier, the driver issued DMA transations even in case of OE which shouldn't be done according to the OE handling mechanism mentioned above, as we are resetting the FIFO's, refer section: "12.1.6.4.8.1.3.6 Overrun During Receive" [0]. [0] https://www.ti.com/lit/pdf/spruiu1 Signed-off-by: Moteen Shah Link: https://patch.msgid.link/20260112081829.63049-2-m-shah@ti.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

serial: 8250_dw: handle clock enable errors in runtime_resume

2026-03-04T12:20:32Z

[ Upstream commit d31228143a489ba6ba797896a07541ce06828c09 ] Add error checking for clk_prepare_enable() calls in dw8250_runtime_resume(). Currently if either clock fails to enable, the function returns success while leaving clocks in inconsistent state. This change implements comprehensive error handling by checking the return values of both clk_prepare_enable() calls. If the second clock enable operation fails after the first clock has already been successfully enabled, the code now properly cleans up by disabling and unpreparing the first clock before returning. The error code is then propagated to the caller, ensuring that clock enable failures are properly reported rather than being silently ignored. Signed-off-by: Artem Shimko Link: https://patch.msgid.link/20251104145433.2316165-2-a.shimko.dev@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

serial: SH_SCI: improve "DMA support" prompt

2026-02-26T22:59:33Z

[ Upstream commit 93bb95a11238d66a4c9aa6eabf9774b073a5895c ] Having a prompt of "DMA support" suddenly appear during a "make oldconfig" can be confusing. Add a little helpful text to the prompt message. Fixes: 73a19e4c0301 ("serial: sh-sci: Add DMA support.") Signed-off-by: Randy Dunlap Reviewed-by: Geert Uytterhoeven Link: https://patch.msgid.link/20260110232643.3533351-5-rdunlap@infradead.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

serial: imx: change SERIAL_IMX_CONSOLE to bool

2026-02-26T22:59:33Z

[ Upstream commit 79527d86ba91c2d9354832d19fd12b3baa66bd10 ] SERIAL_IMX_CONSOLE is a build option for the imx driver (SERIAL_IMX). It does not build a separate console driver file, so it can't be built as a module since it isn't built at all. Change the Kconfig symbol from tristate to bool and update the help text accordingly. Fixes: 0db4f9b91c86 ("tty: serial: imx: enable imx serial console port as module") Signed-off-by: Randy Dunlap Link: https://patch.msgid.link/20260110232643.3533351-2-rdunlap@infradead.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

treewide: Drop pci_save_state() after pci_restore_state()

2026-02-11T12:41:45Z

commit 383d89699c5028de510a6667f674ed38585f77fc upstream. In 2009, commit c82f63e411f1 ("PCI: check saved state before restore") changed the behavior of pci_restore_state() such that it became necessary to call pci_save_state() afterwards, lest recovery from subsequent PCI errors fails. The commit has just been reverted and so all the pci_save_state() after pci_restore_state() calls that have accumulated in the tree are now superfluous. Drop them. Two drivers chose a different approach to achieve the same result: drivers/scsi/ipr.c and drivers/net/ethernet/intel/e1000e/netdev.c set the pci_dev's "state_saved" flag to true before calling pci_restore_state(). Drop this as well. Signed-off-by: Lukas Wunner Signed-off-by: Bjorn Helgaas Acked-by: Dave Jiang Acked-by: Giovanni Cabiddu # qat Link: https://patch.msgid.link/c2b28cc4defa1b743cf1dedee23c455be98b397a.1760274044.git.lukas@wunner.de Cc: Mario Limonciello Signed-off-by: Greg Kroah-Hartman

serial: Fix not set tty->port race condition

2026-01-30T09:32:13Z

commit 32f37e57583f869140cff445feedeea8a5fea986 upstream. 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

serial: 8250_pci: Fix broken RS485 for F81504/508/512

2026-01-30T09:32:13Z

commit 27aff0a56b3c77ea1a73641c9b3c4172a8f7238f upstream. 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

serial: sh-sci: Check that the DMA cookie is valid

2026-01-02T11:57:15Z

commit c3ca8a0aac832fe8047608bb2ae2cca314c6d717 upstream. The driver updates struct sci_port::tx_cookie to zero right before the TX work is scheduled, or to -EINVAL when DMA is disabled. dma_async_is_complete(), called through dma_cookie_status() (and possibly through dmaengine_tx_status()), considers cookies valid only if they have values greater than or equal to 1. Passing zero or -EINVAL to dmaengine_tx_status() before any TX DMA transfer has started leads to an incorrect TX status being reported, as the cookie is invalid for the DMA subsystem. This may cause long wait times when the serial device is opened for configuration before any TX activity has occurred. Check that the TX cookie is valid before passing it to dmaengine_tx_status(). Fixes: 7cc0e0a43a91 ("serial: sh-sci: Check if TX data was written to device in .tx_empty()") Cc: stable Signed-off-by: Claudiu Beznea Link: https://patch.msgid.link/20251217135759.402015-1-claudiu.beznea.uj@bp.renesas.com Signed-off-by: Greg Kroah-Hartman

serial: xilinx_uartps: fix rs485 delay_rts_after_send

2026-01-02T11:57:15Z

commit 267ee93c417e685d9f8e079e41c70ba6ee4df5a5 upstream. RTS line control with delay should be triggered when there is no more bytes in kfifo and hardware buffer is empty. Without this patch RTS control is scheduled right after feeding hardware buffer and this is too early. RTS line may change state before hardware buffer is empty. With this patch delayed RTS state change is triggered when function cdns_uart_handle_tx is called from cdns_uart_isr on CDNS_UART_IXR_TXEMPTY exactly when hardware completed transmission Fixes: fccc9d9233f9 ("tty: serial: uartps: Add rs485 support to uartps driver") Cc: stable Link: https://patch.msgid.link/20251221103221.1971125-1-jakub.turek@elsta.tech Signed-off-by: Jakub Turek Signed-off-by: Greg Kroah-Hartman