It's strongly recommended for GPIO drivers to always implement the
.get_direction() callback - even when the direction is tracked in
software. The GPIO core emits a warning when the callback is missing
and a user reads the direction of a line, e.g. via
/sys/kernel/debug/gpio.
Fixes: dfeae619d781 ("serial: sc16is7xx")
Cc: stable <stable@kernel.org>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Acked-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Link: https://patch.msgid.link/20260716210813.2582826-1-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit b1b4efea05a5 ("serial: 8250_mid: Disable DMA for selected
platforms") replaced the dnv_board setup and exit callbacks with
PTR_IF(false, ...), which evaluates to NULL. However, the three call
sites in mid8250_probe() and mid8250_remove() unconditionally
dereference these function pointers without NULL checks, causing a NULL
pointer dereference (kernel oops) on any Denverton (DNV), Ice Lake Xeon
D (ICX-D/CDF), or Snowridge (SNR) platform.
Fix this by adding the missing NULL checks before calling the setup and
exit callbacks.
Fixes: b1b4efea05a5 ("serial: 8250_mid: Disable DMA for selected platforms")
Cc: stable <stable@kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Jiangshan Yi <yijiangshan@kylinos.cn>
Link: https://patch.msgid.link/20260715073546.1875083-1-yijiangshan@kylinos.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull tty/serial fixes from Greg KH:
"Here are some small tty/serial/vt fixes for 7.2-rc3 that resolve some
reported problems. Included in here are:
- vt spurious modifier issue that showed up in -rc1 (reported a
bunch)
- 8250 driver bugfixes
- msm serial driver bugfix
- max310x serial driver bugfix
All of these have been in linux-next with no reported issues"
* tag 'tty-7.2-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
serial: 8250: Ignore flow control on suspend/resume with no_console_suspend
serial: 8250_mid: Disable DMA for selected platforms
serial: 8250_omap: clear rx_running on zero-length DMA completes
vt: fix spurious modifier in CSI/cursor key sequences
serial: msm: Disable DMA for kernel console UART
serial: max310x: implement gpio_chip::get_direction()
If no_console_suspend is specified, on suspend the 8250 console driver
uses a scratch register (UART_SCR) to store a special canary value. This
is used during the resume path to identify a printk() call before the
driver's own ->resume() callback. In this case,
serial8250_console_restore() is called to quickly re-init the 8250 for
console printing.
See commit 4516d50aabed ("serial: 8250: Use canary to restart console after
suspend") for the original motivation.
Unfortunately, this canary workaround does not work in all cases (such as
suspend to mem) because the scratch register will not reset. This has not
been a real issue until now because it could simply lead to some garbage
characters upon resume. However, with the introduction of console flow
control it becomes a real problem because a failed suspend/resume detection
when flow control is enabled leads to all characters hitting the flow
control timeout.
Workaround this issue by temporarily ignoring console flow control when
the debug canary suspend/resume detection is active.
Fixes: 5e6dfb87b191 ("serial: 8250: Add support for console flow control")
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Link: https://patch.msgid.link/20260707141032.5074-1-john.ogness@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In accordance with Errata (specification updates)
HSUART May Stop Functioning when DMA is Active.
- Denverton document #572409, rev 3.4, DNV60
- Ice Lake Xeon D document #714070, ICXD65
- Snowridge document #731931, SNR44
For a quick fix just disable the respective callbacks during the device probe.
Depending on the future development we might remove them completely.
Reported-by: micas-opensource <zjianan156@gmail.com>
Closes: https://lore.kernel.org/linux-serial/20250625031409.2404219-1-opensource@ruijie.com.cn/
Fixes: 6ede6dcd87aa ("serial: 8250_mid: add support for DMA engine handling from UART MMIO")
Cc: stable <stable@kernel.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patch.msgid.link/20260626094937.561776-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
On AM33xx RX DMA only triggers when the FIFO reaches the
configured threshold (typically 48 bytes). For smaller bursts
no DMA request is issued and the FIFO is drained by RX timeout.
In this case __dma_rx_do_complete() can legitimately see count == 0.
The current code exits early in this case and does not clear
dma->rx_running, leaving the DMA state inconsistent. This can
prevent RX DMA from restarting and may cause
omap_8250_rx_dma_flush() to fail, marking DMA as broken.
Fix this by clearing dma->rx_running once the DMA transfer has
completed or been terminated, even if no data was transferred.
Fixes: a5fd8945a478 ("serial: 8250: 8250_omap.c: Clear DMA RX running status only after DMA termination is done")
Cc: stable <stable@kernel.org>
Signed-off-by: Matthias Feser <mfe@KBSgmbhfr.onmicrosoft.com>
Reviewed-by: Moteen Shah <m-shah@ti.com>
Link: https://patch.msgid.link/BE3P281MB55155F2F5795E411F5A65282EE0B2@BE3P281MB5515.DEUP281.PROD.OUTLOOK.COM
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
csi_modifier_param() builds the xterm modifier parameter from
shift_state, counting KG_SHIFTL/KG_SHIFTR as Shift, KG_ALTGR as Alt
and KG_CTRLL/KG_CTRLR as Ctrl in addition to the canonical KG_SHIFT,
KG_ALT and KG_CTRL.
That is wrong when those weights are not plain modifiers. Keymaps
derived from XKB layouts (by kbd's xkbsupport, and by the
console-setup used in Debian, Ubuntu and others) encode the active
layout group using KG_SHIFTL/KG_SHIFTR:
group 1: -
group 2: shiftl
group 3: shiftr
group 4: shiftl | shiftr
So while a non-default layout group is selected, KG_SHIFTL and/or
KG_SHIFTR are set in shift_state with no Shift key held.
csi_modifier_param() then adds a spurious Shift to every cursor and
CSI key: pressing Up while group 2 is active emits ESC[1;2A (Shift+Up)
instead of ESC[A. KG_ALTGR has the same problem since it is the
standard third-level selector.
Normal keymaps bind the physical Shift/Ctrl/Alt keys to KG_SHIFT,
KG_CTRL and KG_ALT, leaving the left/right and AltGr weights free for
layout and level selection. Count only those canonical weights, so
genuine modifiers are still encoded while layout/level selectors are
not.
Fixes: 4af70f151671 ("vt: add modifier support to cursor keys")
Reported-by: Alexey Gladkov <legion@kernel.org>
Closes: https://lore.kernel.org/kbd/aj2gR0Y7sM6i9s2G@example.org/
Cc: stable <stable@kernel.org>
Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
Link: https://patch.msgid.link/20260626024833.3419086-1-nico@fluxnic.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
At the moment, concurrent writes from userspace and the kernel to the
console can trigger a race condition that results in an infinite loop of
the same messages printed over and over again. This is most likely to
happen during system startup or shutdown when the init system starts/stops
a large number of system services that interact with various kernel code.
When userspace writes to the TTY device, the driver initiates an
asynchronous DMA transfer and releases the port lock. At the same moment,
the kernel printk path might grab the port lock and re-configure the UART
controller for PIO, without waiting for the DMA operation to complete. It
seems like this collision results in zero progress being reported for the
DMA engine, so the same text is printed to the console over and over again.
For the kernel console, we want a reliable output path that will be
functional even during crashes etc. So rather than implementing complex
code to synchronize the kernel console write routines with the userspace
DMA write routines, simply disable DMA for the console UART instance.
Similar checks exist in many other serial drivers, e.g. 8250_port.c,
imx.c, sh-sci.c etc.
Cc: stable <stable@kernel.org>
Fixes: 3a878c430fd6 ("tty: serial: msm: Add TX DMA support")
Signed-off-by: Stephan Gerhold <stephan.gerhold@linaro.org>
Acked-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Link: https://patch.msgid.link/20260706-serial-msm-console-dma-collision-v1-1-3179b8cb1d89@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
It's strongly recommended for GPIO drivers to always implement the
.get_direction() callback - even when the direction is tracked in
software. The GPIO core emits a warning when the callback is missing
and a user reads the direction of a line, e.g. via
/sys/kernel/debug/gpio.
The MAX310X keeps the GPIO direction in the GPIOCFG register (a set bit
selects output), which the existing direction_input/output callbacks
already program, so the current direction can be read back directly.
Fixes: f65444187a66 ("serial: New serial driver MAX310X")
Cc: stable <stable@kernel.org>
Signed-off-by: Tapio Reijonen <tapio.reijonen@vaisala.com>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Reviewed-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://patch.msgid.link/20260615-b4-serial-max310x-gpio-get-direction-v2-1-4704ba2b181a@vaisala.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Replace the #include of <linux/mod_devicetable.h> by the more specific <linux/device-id/*.h> where applicable. For most cases the include can be dropped completely, only a few drivers need one or two headers added. Acked-by: Danilo Krummrich <dakr@kernel.org> Acked-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Acked-by: Bjorn Helgaas <bhelgaas@google.com> Link: https://patch.msgid.link/1a3f2007c5c5dcf555c09a4035ce3ae8ef1b6c49.1782808461.git.u.kleine-koenig@baylibre.com Signed-off-by: Uwe Kleine-König (The Capable Hub) <u.kleine-koenig@baylibre.com>