linux.git/drivers/char/vt.c, branch v2.6.30

Revert "console ASCII glyph 1:1 mapping"

2009-04-19T17:51:40+00:00

This reverts commit 1c55f18717304100a5f624c923f7cb6511b4116d.

Ingo Brueckl was assuming that reverting to 1:1 mapping for chars >= 128
was not useful, but it happens to be: due to the limitations of the
Linux console, when a blind user wants to read BIG5 on it, he has no
other way than loading a font without SFM and let the 1:1 mapping permit
the screen reader to get the BIG5 encoding.

Signed-off-by: Samuel Thibault 
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds

vcs: hook sysfs devices into object lifetime instead of "binding"

2009-03-24T23:38:26+00:00

During bootup performance tracing I noticed many occurrences of
vca* device creation and removal, leading to the usual userspace
uevent processing, which are, in this case, rather pointless.

A simple test showing the kernel timing (not including all the
work userspace has to do), gives us these numbers:
  $ time for i in `seq 1000`; do echo a > /dev/tty2; done
  real    0m1.142s
  user    0m0.015s
  sys     0m0.540s

If we move the hook for the vcs* driver core devices from the
tty "binding" to the vc allocation/deallocation, which is what
the vcs* devices represent, we get the following numbers:
  $ time for i in `seq 1000`; do echo a > /dev/tty2; done
  real    0m0.152s
  user    0m0.030s
  sys     0m0.072s

Cc: Alan Cox 
Signed-off-by: Kay Sievers 
Signed-off-by: Greg Kroah-Hartman

Make various things static

2009-01-08T16:31:15+00:00

Building an allnoconfig kernel, sparse asked whether these could be
static, so I checked, and they are only used in the file where they are
declared.

Signed-off-by: Roel Kluin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

pty: simplify resize

2009-01-02T18:19:36+00:00

We have special case logic for resizing pty/tty pairs. We also have a per
driver resize method so for the pty case we should use it.

Signed-off-by: Alan Cox 
Signed-off-by: Linus Torvalds

n_tty: Fix loss of echoed characters and remove bkl from n_tty

2009-01-02T18:19:35+00:00

Fixes the loss of echoed (and other ldisc-generated characters) when
the tty is stopped or when the driver output buffer is full (happens
frequently for input during continuous program output, such as ^C)
and removes the Big Kernel Lock from the N_TTY line discipline.

Adds an "echo buffer" to the N_TTY line discipline that handles all
ldisc-generated output (including echoed characters).  Along with the
loss of characters, this also fixes the associated loss of sync between
tty output and the ldisc state when characters cannot be immediately
written to the tty driver.

The echo buffer stores (in addition to characters) state operations that need
to be done at the time of character output (like management of the column
position).  This allows echo to cooperate correctly with program output,
since the ldisc state remains consistent with actual characters written.

Since the echo buffer code now isolates the tty column state code
to the process_out* and process_echoes functions, we can remove the
Big Kernel Lock (BKL) and replace it with mutex locks.

Highlights are:

* Handles echo (and other ldisc output) when tty driver buffer is full
  - continuous program output can block echo
* Saves echo when tty is in stopped state (e.g. ^S)
  - (e.g.: ^Q will correctly cause held characters to be released for output)
* Control character pairs (e.g. "^C") are treated atomically and not
  split up by interleaved program output
* Line discipline state is kept consistent with characters sent to
  the tty driver
* Remove the big kernel lock (BKL) from N_TTY line discipline

Signed-off-by: Joe Peterson 
Signed-off-by: Alan Cox 
Signed-off-by: Linus Torvalds

console ASCII glyph 1:1 mapping

2008-12-13T19:25:49+00:00

For the console, there is a 1:1 mapping of glyphs which cannot be found
in the current font.  This seems to be meant as a kind of 'emergency
fallback' for fonts without unicode mapping which otherwise would
display nothing readable on the screen.

At the moment it affects all chars for which no substitution character
is defined.  In particular this means that for all chars (>= 128) where
there is no iso88591-1/unicode character (e.g.  control character area)
you'll get the very strange 1:1 mapping of the (cp437) graphics card
glyphs.

I'm pretty sure that the 1:1 mapping should only affect strict ASCII
code characters, i.e.  chars < 128.

The patch limits the mapping as it probably was meant anyway.

Signed-off-by: Ingo Brueckl 
Acked-by: H. Peter Anvin 
Cc: Egmont Koblinger 
Signed-off-by: Linus Torvalds

vt: incomplete initialization of vc_tab_stop

2008-11-06T23:41:17+00:00

Problem 1 (see patch below):
  vc_tab_stop is declared as an array of 8 unsigned ints in struct
  vc_data in include/linux/console_struct.h .
  In drivers/char/vt.c only 5 of these 8 unsigned ints get initialized
  leading to unintended tabulator placement on displays with more than
  160 columns text.

Problem 2 (open):
  Upcoming displays will have more than 256 columns of text leading to
  invalid memory access in drivers/char/vt.c during tabulator
  calculations:
    if (vc->vc_tab_stop[vc->vc_x >> 5] & (1 << (vc->vc_x & 31)))
	break;

Signed-off-by: Wolfgang Kroworsch 
Cc: Alan Cox 
Cc: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Remove Andrew Morton's old email accounts

2008-10-16T18:21:32+00:00

People can use the real name an an index into MAINTAINERS to find the
current email address.

Signed-off-by: Francois Cami 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Revert "vt: fix background color on line feed"

2008-10-14T19:12:02+00:00

This reverts commit c9e587abfdec2c2aaa55fab83bcb4972e2f84f9b, and the
subsequent commits that fixed it up:

 - afa9b649 "fbcon: prevent cursor disappearance after switching to 512
   character font"

 - d850a2fa "vt/fbcon: fix background color on line feed"

 - 7fe3915a "vt/fbcon: update scrl_erase_char after 256/512-glyph font
   switch"

by request of Alan Cox. Quoth Alan:
  "Unfortunately it's wrong and its been causing breakages because
   various apps like ncurses expect our previous (and correct)
   behaviour."

Alexander sent out a similar patch.

Requested-by: Alan Cox 
Tested-by: Jan Engelhardt 
Cc: Alexander V. Lukyanov 
Signed-off-by: Linus Torvalds

tty: Remove more special casing and out of place code

2008-10-13T16:51:42+00:00

Carry on pushing code out of tty_io when it belongs to other drivers. I'm
not 100% happy with some of this and it will be worth revisiting some of the
exports later when the restructuring work is done.

Signed-off-by: Alan Cox 
Signed-off-by: Linus Torvalds