user/sven/linux.git/include/linux/console.h, branch v5.4.224

serial: core: Fix initializing and restoring termios speed

2021-11-17T08:48:25Z

commit 027b57170bf8bb6999a28e4a5f3d78bf1db0f90c upstream. Since commit edc6afc54968 ("tty: switch to ktermios and new framework") termios speed is no longer stored only in c_cflag member but also in new additional c_ispeed and c_ospeed members. If BOTHER flag is set in c_cflag then termios speed is stored only in these new members. Therefore to correctly restore termios speed it is required to store also ispeed and ospeed members, not only cflag member. In case only cflag member with BOTHER flag is restored then functions tty_termios_baud_rate() and tty_termios_input_baud_rate() returns baudrate stored in c_ospeed / c_ispeed member, which is zero as it was not restored too. If reported baudrate is invalid (e.g. zero) then serial core functions report fallback baudrate value 9600. So it means that in this case original baudrate is lost and kernel changes it to value 9600. Simple reproducer of this issue is to boot kernel with following command line argument: "console=ttyXXX,86400" (where ttyXXX is the device name). For speed 86400 there is no Bnnn constant and therefore kernel has to represent this speed via BOTHER c_cflag. Which means that speed is stored only in c_ospeed and c_ispeed members, not in c_cflag anymore. If bootloader correctly configures serial device to speed 86400 then kernel prints boot log to early console at speed speed 86400 without any issue. But after kernel starts initializing real console device ttyXXX then speed is changed to fallback value 9600 because information about speed was lost. This patch fixes above issue by storing and restoring also ispeed and ospeed members, which are required for BOTHER flag. Fixes: edc6afc54968 ("[PATCH] tty: switch to ktermios and new framework") Cc: stable@vger.kernel.org Signed-off-by: Pali Rohár Link: https://lore.kernel.org/r/20211002130900.9518-1-pali@kernel.org Signed-off-by: Greg Kroah-Hartman

panic: add an option to replay all the printk message in buffer

2019-05-18T22:52:26Z

Currently on panic, kernel will lower the loglevel and print out pending printk msg only with console_flush_on_panic(). Add an option for users to configure the "panic_print" to replay all dmesg in buffer, some of which they may have never seen due to the loglevel setting, which will help panic debugging . [feng.tang@intel.com: keep the original console_flush_on_panic() inside panic()] Link: http://lkml.kernel.org/r/1556199137-14163-1-git-send-email-feng.tang@intel.com [feng.tang@intel.com: use logbuf lock to protect the console log index] Link: http://lkml.kernel.org/r/1556269868-22654-1-git-send-email-feng.tang@intel.com Link: http://lkml.kernel.org/r/1556095872-36838-1-git-send-email-feng.tang@intel.com Signed-off-by: Feng Tang Reviewed-by: Petr Mladek Cc: Aaro Koskinen Cc: Petr Mladek Cc: Steven Rostedt Cc: Sergey Senozhatsky Cc: Kees Cook Cc: Borislav Petkov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

console: Replace #if 0 with atomic var 'ignore_console_lock_warning'

2018-07-31T11:06:57Z

The macro WARN_CONSOLE_UNLOCKED prints a warning when a thread enters the console's critical section without having acquired the console lock. The console lock can be ignored when debugging the console using printk, but this makes WARN_CONSOLE_UNLOCKED generate unnecessary warnings. The variable ignore_console_lock_warning temporarily disables WARN_CONSOLE_UNLOCKED. Developers interested in debugging the console's critical sections should increment it before entering the CS and decrement it after leaving the CS. Setting ignore_console_lock_warning is only for debugging. Regular operation should not manipulate it. Acknoledgements: This patch is based on an earlier version by Steven Rostedt. The use of atomic increment/decrement was suggested by Petr Mladek. Link: http://lkml.kernel.org/r/717e6337-e7a6-7a92-1c1b-8929a25696b5@suse.de Signed-off-by: Thomas Zimmermann Acked-by: Hans de Goede Acked-by: Petr Mladek Reviewed-by: Sergey Senozhatsky Cc: Steven Rostedt (VMware) Cc: Andrew Morton [b.zolnierkie: use ] Signed-off-by: Bartlomiej Zolnierkiewicz

console/fbcon: Add support for deferred console takeover

2018-06-28T13:20:30Z

Currently fbcon claims fbdevs as soon as they are registered and takes over the console as soon as the first fbdev gets registered. This behavior is undesirable in cases where a smooth graphical bootup is desired, in such cases we typically want the contents of the framebuffer (typically a vendor logo) to stay in place as is. The current solution for this problem (on embedded systems) is to not enable fbcon. This commit adds a new FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER config option, which when enabled defers fbcon taking over the console from the dummy console until the first text is displayed on the console. Together with the "quiet" kernel commandline option, this allows fbcon to still be used together with a smooth graphical bootup, having it take over the console as soon as e.g. an error message is logged. Note the choice to detect the first console output in the dummycon driver, rather then handling this entirely inside the fbcon code, was made after 2 failed attempts to handle this entirely inside the fbcon code. The fbcon code is woven quite tightly into the console code, making this to only feasible option. Reviewed-by: Daniel Vetter Signed-off-by: Hans de Goede Signed-off-by: Bartlomiej Zolnierkiewicz

console: Fill in struct consw argument names

2018-02-27T09:17:33Z

Reading the function declarations for the console callbacks lacks any hints as to what the arguments are. Instead of going and digging around in various implementations that may each only have a subset of the callbacks, name all the arguments in the declaration. This has no functional change. Signed-off-by: Kees Cook Signed-off-by: Greg Kroah-Hartman

console: move console_init() out of tty_io.c

2017-04-18T16:01:52Z

All the console driver handling code lives in printk.c. Move console_init() there as well so console support can still be used when the TTY code is configured out. No logical changes from this patch. Signed-off-by: Nicolas Pitre Signed-off-by: Greg Kroah-Hartman

console: Add callback to flush scrollback buffer to consw struct

2017-01-25T10:54:02Z

This new callback is in preparation for persistent scrollback buffer support for VGA consoles. With a single scrollback buffer for all consoles, we could flush the buffer just by invocating consw->con_switch(). But when each VGA console has its own scrollback buffer, we need a new callback to tell the video console driver which buffer to flush. Signed-off-by: Manuel Schölling Reviewed-by: Andrey Utkin Tested-by: Andrey Utkin Tested-by: Adam Borowski Signed-off-by: Greg Kroah-Hartman

Merge tag 'tty-4.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2016-12-13T19:18:24Z

Pull tty/serial updates from Greg KH: "Here's the tty/serial patchset for 4.10-rc1. It's been a quiet kernel cycle for this subsystem, just a small number of changes. A few new serial drivers, and some cleanups to the old vgacon logic, and other minor serial driver changes as well. All of these have been in linux-next for a while with no reported issues" * tag 'tty-4.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (54 commits) serial: 8250_mid fix calltrace when hotplug 8250 serial controller console: Move userspace I/O out of console_lock to fix lockdep warning tty: nozomi: avoid sprintf buffer overflow serial: 8250_pci: Detach low-level driver during PCI error recovery serial: core: don't check port twice in a row mxs-auart: count FIFO overrun errors serial: 8250_dw: Add support for IrDA SIR mode serial: 8250: Expose set_ldisc function serial: 8250: Add IrDA to UART capabilities serial: 8250_dma: power off device after TX is done serial: 8250_port: export serial8250_rpm_{get|put}_tx() serial: sunsu: Free memory when probe fails serial: sunhv: Free memory when remove() is called vt: fix Scroll Lock LED trigger name tty: typo in comments in drivers/tty/vt/keyboard.c tty: amba-pl011: Add earlycon support for SBSA UART tty: nozomi: use permission-specific DEVICE_ATTR variants tty: serial: Make the STM32 serial port depend on it's arch serial: ifx6x60: Free memory when probe fails serial: ioc4_serial: Free memory when kzalloc fails during probe ...

Revert "console: don't prefer first registered if DT specifies stdout-path"

2016-11-11T16:12:37Z

This reverts commit 05fd007e4629 ("console: don't prefer first registered if DT specifies stdout-path"). The reverted commit changes existing behavior on which many ARM boards rely. Many ARM small-board-computers, like e.g. the Raspberry Pi have both a video output and a serial console. Depending on whether the user is using the device as a more regular computer; or as a headless device we need to have the console on either one or the other. Many users rely on the kernel behavior of the console being present on both outputs, before the reverted commit the console setup with no console= kernel arguments on an ARM board which sets stdout-path in dt would look like this: [root@localhost ~]# cat /proc/consoles ttyS0 -W- (EC p a) 4:64 tty0 -WU (E p ) 4:1 Where as after the reverted commit, it looks like this: [root@localhost ~]# cat /proc/consoles ttyS0 -W- (EC p a) 4:64 This commit reverts commit 05fd007e4629 ("console: don't prefer first registered if DT specifies stdout-path") restoring the original behavior. Fixes: 05fd007e4629 ("console: don't prefer first registered if DT specifies stdout-path") Link: http://lkml.kernel.org/r/20161104121135.4780-2-hdegoede@redhat.com Signed-off-by: Hans de Goede Cc: Paul Burton Cc: Rob Herring Cc: Frank Rowand Cc: Thorsten Leemhuis Cc: Greg Kroah-Hartman Cc: Tejun Heo Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

tty: vt, cleanup and document con_scroll

2016-10-27T14:37:43Z

Scrolling helpers scrup and scrdown both accept 'top' and 'bottom' as unsigned int. Number of lines 'nr' is accepted as int, but all callers pass down unsigned too. So change the type of 'nr' to unsigned too. Now, promote unsigned int from the helpers up to the con_scroll hook which actually accepted all those as signed int. Next, the 'dir' parameter can have only two values and we define constants for that: SM_UP and SM_DOWN. Switch them to enum and do proper type checking on 'dir' too. Finally, document the behaviour of the hook. Signed-off-by: Jiri Slaby Cc: Thomas Winischhofer Cc: Tomi Valkeinen Cc: "James E.J. Bottomley" Cc: Helge Deller Cc: Cc: Cc: Signed-off-by: Greg Kroah-Hartman