linux-toradex.git/drivers/tty/vt/keyboard.c, branch v6.5

tty: Fix the keyboard led light display problem

2021-12-21T08:19:14+00:00

Use the "ctrl+alt+Fn" key combination to switch the system from tty to
desktop or switch the system from desktop to tty. After the switch is
completed, it is found that the state of the keyboard lock is
inconsistent with the state of the keyboard Led light.The reasons are
as follows:

* The desktop environment (Xorg and other services) is bound to a tty
  (assuming it is tty1), and the kb->kbdmode attribute value of tty1
  will be set to VC_OFF. According to the current code logic, in the
  desktop environment, the values of ledstate and kb->ledflagstate
  of tty1 will not be modified anymore, so they are always 0.

* When switching between each tty, the final value of ledstate set by
  the previous tty is compared with the kb->ledflagstate value of the
  current tty to determine whether to set the state of the keyboard
  light. The process of switching between desktop and tty is also the
  process of switching between tty1 and other ttys. There are two
  situations:

  - (1) In the desktop environment, tty1 will not set the ledstate,
  which will cause when switching from the desktop to other ttys,
  if the desktop lights up the keyboard's led, after the switch is
  completed, the keyboard's led light will always be on;

  - (2) When switching from another tty to the desktop, this
  mechanism will trigger tty1 to set the led state. If other tty
  lights up the led of the keyboard before switching to the desktop,
  the led will be forcibly turned off. This situation should
  be avoided.

* The current patch is to solve these problems: When VT is switched,
  the keyboard led needs to be set once.Ensure that after the
  switch is completed, the state of the keyboard LED is consistent
  with the state of the keyboard lock.

Suggested-by: Dmitry Torokhov 
Reviewed-by: Dmitry Torokhov 
Signed-off-by: lianzhi chang 
Link: https://lore.kernel.org/r/20211215125125.10554-1-changlianzhi@uniontech.com
Signed-off-by: Greg Kroah-Hartman

tty: drivers/tty/, stop using tty_schedule_flip()

2021-11-25T17:35:23+00:00

Since commit a9c3f68f3cd8d (tty: Fix low_latency BUG) in 2014,
tty_flip_buffer_push() is only a wrapper to tty_schedule_flip(). We are
going to remove the latter (as it is used less), so call the former in
drivers/tty/.

Cc: Vladimir Zapolskiy 
Reviewed-by: Johan Hovold 
Signed-off-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20211122111648.30379-2-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman

vt: keyboard.c: make console an unsigned int

2021-07-27T10:23:20+00:00

The console variable is used everywhere in some fun pointer path and
array indexes and for some reason isn't always declared as unsigned.
This plays havoc with some static analysis tools so mark the variable as
unsigned so we "know" we can not wrap the arrays backwards here.

Cc: Jiri Slaby 
Cc: Andy Shevchenko 
Reported-by: Jordy Zomer 
Link: https://lore.kernel.org/r/20210726134322.2274919-2-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman

vt: keyboard: treat kbd_table as an array all the time.

2021-07-27T10:23:18+00:00

The keyboard.c code seems to like to treat the kbd_table as both an
array, and as a base to do some pointer math off of.  As they really are
the same thing, and compilers are smart enough not to make a difference
anymore, just be explicit and always use this as an array to make the
code more obvious for all to read.

Cc: Jiri Slaby 
Cc: Andy Shevchenko 
Cc: Jordy Zomer 
Link: https://lore.kernel.org/r/20210726134322.2274919-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman

tty: cumulate and document tty_struct::flow* members

2021-05-13T14:57:16+00:00

Group the flow flags under a single struct called flow. The new struct
contains 'stopped' and 'tco_stopped' bools which used to be bits in a
bitfield. The struct also contains the lock protecting them to
potentially share the same cache line.

Note that commit c545b66c6922b (tty: Serialize tcflow() with other tty
flow control changes) added a padding to the original bitfield. It was
for the bitfield to occupy a whole 64b word to avoid interferring stores
on Alpha (cannot we evaporate this arch with weird implications to C
code yet?). But it doesn't work as expected as the padding
(tty_struct::unused) is aligned to a 8B boundary too and occupies some
bytes from the next word.

So make it reliable by:
1) setting __aligned of the struct -- that aligns the start, and
2) making 'unsigned long unused[0]' as the last member of the struct --
   pads the end.

This is also the perfect time to start the documentation of tty_struct
where all this lives. So we start by documenting what these bools
actually serve for. And why we do all the alignment dances. Only the few
up-to-date information from the Theodore's comment made it into this new
Kerneldoc comment.

Signed-off-by: Jiri Slaby 
Cc: "David S. Miller" 
Cc: Jakub Kicinski 
Cc: Jonathan Corbet 
Cc: Arnd Bergmann 
Cc: Ulf Hansson 
Cc: Heiko Carstens 
Cc: Vasily Gorbik 
Cc: Christian Borntraeger 
Cc: Shawn Guo 
Cc: Sascha Hauer 
Cc: Vineet Gupta 
Cc: "Maciej W. Rozycki" 
Link: https://lore.kernel.org/r/20210505091928.22010-13-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman

vt: keyboard, Fix typo in the doc for vt_get_shift_state()

2021-03-23T09:39:27+00:00

Kernel documentation validator is not happy:

.../keyboard.c:2195: warning: expecting prototype for vt_get_shiftstate(). Prototype was for vt_get_shift_state() instead

This is due to typo, fix it here.

Reviewed-by: Jiri Slaby 
Signed-off-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20210303083229.75784-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

vt: keyboard, use new API for keyboard_tasklet

2021-01-27T17:08:07+00:00

This converts the keyboard_tasklet to use the new API in
commit 12cc923f1ccc ("tasklet: Introduce new initialization API")

The new API changes the argument passed to the callback function, but
fortunately the argument isn't used so it is straight forward to use
DECLARE_TASKLET_DISABLED() rather than DECLARE_TASKLET_DISABLED_OLD().

Signed-off-by: Emil Renner Berthing 
Link: https://lore.kernel.org/r/20210127164222.13220-1-kernel@esmil.dk
Signed-off-by: Greg Kroah-Hartman

vt: keyboard, make keyboard_tasklet local

2021-01-07T15:17:31+00:00

Now that the last extern user of the tasklet (set_leds) is in
keyboard.c, we can make keyboard_tasklet local to this unit too.

Signed-off-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20210105120239.28031-2-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman

vt: move set_leds to keyboard.c

2021-01-07T15:17:31+00:00

set_leds and compute_shiftstate are called from a single place in vt.c.
Let's combine these two into vt_set_leds_compute_shiftstate. This allows
for making keyboard_tasklet local in the next patch.

Signed-off-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20210105120239.28031-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman

vt: keyboard, make use of assign_bit() API

2020-11-12T08:43:51+00:00

We have for some time the assign_bit() API to replace open coded

	if (foo)
		set_bit(n, bar);
	else
		clear_bit(n, bar);

Use this API in VT keyboard library code.

Acked-by: Jiri Slaby 
Signed-off-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20201109105601.47159-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman