- 14 12月, 2008 1 次提交
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由 Ingo Brueckl 提交于
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: NIngo Brueckl <ib@wupperonline.de> Acked-by: NH. Peter Anvin <hpa@zytor.com> Cc: Egmont Koblinger <egmont@uhulinux.hu> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 07 11月, 2008 1 次提交
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由 Wolfgang Kroworsch 提交于
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: NWolfgang Kroworsch <wolfgang@kroworsch.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 17 10月, 2008 1 次提交
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由 Francois Cami 提交于
People can use the real name an an index into MAINTAINERS to find the current email address. Signed-off-by: NFrancois Cami <francois.cami@free.fr> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 15 10月, 2008 1 次提交
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由 Linus Torvalds 提交于
This reverts commit c9e587ab, 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: NAlan Cox <alan@lxorguk.ukuu.org.uk> Tested-by: NJan Engelhardt <jengelh@medozas.de> Cc: Alexander V. Lukyanov <lav@netis.ru> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 14 10月, 2008 4 次提交
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由 Alan Cox 提交于
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: NAlan Cox <alan@redhat.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Alan Cox 提交于
Right now there are various drivers that try to use tty->count to know when they get the final close. Aristeau Rozanski showed while debugging the vt sysfs race that this isn't entirely safe. Instead of driver side tricks to work around this introduce a shutdown which is called when the tty is being destructed. This also means that the shutdown method is tied into the refcounting. Use this to rework the console close/sysfs logic. Remove lots of special case code from the tty core code. The pty code can now have a shutdown() method that replaces the special case hackery in the tree free up paths. Signed-off-by: NAlan Cox <alan@redhat.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Alan Cox 提交于
For hysterical raisins the vt layer drops and retakes locks in the write method. This is a left over from the days when user/kernel data was passed directly to the tty not pre-buffered. Signed-off-by: NAlan Cox <alan@redhat.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Alan Cox 提交于
Right now we have ifdefs and hooks in the core ioctl handler for TIOCLINUX and then test if its a console. This is brain dead. Instead call the tioclinux helper from the relevant driver ioctl methods. Signed-off-by: NAlan Cox <alan@redhat.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 16 8月, 2008 1 次提交
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由 Alan Cox 提交于
This moves it to being a tty operation. That removes special cases and now also means that resize can be picked up by um and other non vt consoles which may have a resize operation. Signed-off-by: NAlan Cox <alan@redhat.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 05 8月, 2008 1 次提交
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由 Alan Cox 提交于
2.6.26 corrected the mutex locking on tty resizing to fix the case where you could get the tty/vt sizing out of sync. That turns out to have a deadlock. The actual fix is really major and I've got it lined up as part of the ops changes for 2.6.28 so for 2.6.26/2.6.27 it is safer to reintroduce this ages old minor bug. Signed-off-by: NAlan Cox <alan@redhat.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 25 7月, 2008 2 次提交
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由 Stefano Stabellini 提交于
vt.c DO_UPDATE macro checks if the console is visible but doesn't check if the console is blanked. In fact updating fbcon while the console is blanked is not only unnecessary but can even cause screen corruption. Therefore I am adding a simple check on console_blanked in DO_UPDATE. Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Krzysztof Helt <krzysztof.h1@poczta.fm> Cc: "Antonino A. Daplas" <adaplas@pol.net> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jiri Slaby 提交于
Hold console sem while creating/destroying sysfs files. Serialisation is so far done by BKL held in tty release_dev and chrdev_open, but no other locks are held in open path. Signed-off-by: NJiri Slaby <jirislaby@gmail.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Aristeu Rozanski <aris@ruivo.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 22 7月, 2008 1 次提交
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由 Greg Kroah-Hartman 提交于
device_create() is race-prone, so use the race-free device_create_drvdata() instead as device_create() is going away. Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
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- 07 6月, 2008 2 次提交
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由 Nick Piggin 提交于
Lockdep says we can't take tasklist lock or sighand lock inside ctrl_lock. Signed-off-by: NNick Piggin <npiggin@suse.de> Acked-by: NAlan Cox <alan@redhat.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jan Engelhardt 提交于
Original report: """I used to force my console to black-on-white by the command `setterm -inversescreen on`. In 2.6.26-rc4, I get lots of black background characters.""" Another addendum to commit c9e587ab. This was previously missed out since I was not aware of what vc_decscnm was for. Signed-off-by: NJan Engelhardt <jengelh@medozas.de> Reported-by: <thunder7@xs4all.nl> Tested-by: <thunder7@xs4all.nl> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 04 6月, 2008 1 次提交
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由 David Woodhouse 提交于
By turning off the new CONSOLE_TRANSLATIONS option and dropping the associated code and tables from the kernel, we can save about 7KiB. Taken from linux-tiny project by Tim Bird and mangled further by dwmw2. Signed-off-by: NTim Bird <tim.bird@am.sony.com> Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>
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- 09 5月, 2008 1 次提交
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由 Samuel Thibault 提交于
For e.g. proper TTY canonical support, IUTF8 termios flag has to be set as appropriate. Linux used to not care about setting that flag for VT TTYs. This patch fixes that by activating it according to the current mode of the VT, and sets the default value according to the vt.default_utf8 parameter. Signed-off-by: NSamuel Thibault <samuel.thibault@ens-lyon.org> Cc: Willy Tarreau <w@1wt.eu> Cc: <stable@kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 30 4月, 2008 4 次提交
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由 Samuel Thibault 提交于
This adds a minimalistic braille screen reader support. This is meant to be used by blind people e.g. on boot failures or when / cannot be mounted etc and thus the userland screen readers can not work. [akpm@linux-foundation.org: fix exports] Signed-off-by: NSamuel Thibault <samuel.thibault@ens-lyon.org> Cc: Jiri Kosina <jikos@jikos.cz> Cc: Dmitry Torokhov <dtor@mail.ru> Acked-by: NAlan Cox <alan@redhat.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Alan Cox 提交于
Signed-off-by: NAlan Cox <alan@redhat.com> Cc: Antonino Daplas <adaplas@pol.net> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Kelly Daly <kelly@au.ibm.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Jiri Slaby <jirislaby@gmail.com> Cc: Samuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Alan Cox 提交于
Historically tty->pgrp and friends were pid_t and the code "knew" they were safe. The change to pid structs opened up a few races and the removal of the BKL in places made them quite hittable. We put tty->pgrp under the ctrl_lock for the tty. Signed-off-by: NAlan Cox <alan@redhat.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Alan Cox 提交于
- Push the BKL down into the line disciplines - Switch the tty layer to unlocked_ioctl - Introduce a new ctrl_lock spin lock for the control bits - Eliminate much of the lock_kernel use in n_tty - Prepare to (but don't yet) call the drivers with the lock dropped on the paths that historically held the lock BKL now primarily protects open/close/ldisc change in the tty layer [jirislaby@gmail.com: a couple of fixes] Signed-off-by: NAlan Cox <alan@redhat.com> Signed-off-by: NJiri Slaby <jirislaby@gmail.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 29 4月, 2008 1 次提交
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由 Jan Engelhardt 提交于
A command that causes a line feed while a background color is active, such as perl -e 'print "x" x 60, "\e[44m", "x" x 40, "\e[0m\n"' and perl -e 'print "x" x 40, "\e[44m\n", "x" x 40, "\e[0m\n"' causes the line that was started as a result of the line feed to be completely filled with the currently active background color instead of the default color. When scrolling, part of the current screen is memcpy'd/memmove'd to the new region, and the new line(s) that will appear as a result are cleared using memset. However, the lines are cleared with vc->vc_video_erase_char, causing them to be colored with the currently active background color. This is different from X11 terminal emulators which always paint the new lines with the default background color (e.g. `xterm -bg black`). The clear operation (\e[1J and \e[2J) also use vc_video_erase_char, so a new vc->vc_scrl_erase_char is introduced with contains the erase character used for scrolling, which is built from vc->vc_def_color instead of vc->vc_color. Signed-off-by: NJan Engelhardt <jengelh@computergmbh.de> Cc: "Antonino A. Daplas" <adaplas@pol.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 28 4月, 2008 1 次提交
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由 Karl Dahlke 提交于
Some accessibility modules need to be able to catch the output on the console before the VT interpretation, and possibly swallow it. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: NSamuel Thibault <samuel.thibault@ens-lyon.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 05 3月, 2008 1 次提交
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由 Samuel Thibault 提交于
VT notifier callbacks need to be aware of console switches. This is already partially done from console_callback(), but at that time fg_console, cursor positions, etc. are not yet updated and hence screen readers fetch the old values. This adds an update notify after all of the values are updated in redraw_screen(vc, 1). Signed-off-by: NSamuel Thibault <samuel.thibault@ens-lyon.org> Cc: <stable@kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 07 2月, 2008 1 次提交
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由 Nick Piggin 提交于
vt is missing a memory barrier to close the critical section. Use a real spinlock for this. Signed-off-by: NNick Piggin <npiggin@suse.de> Cc: "Antonino A. Daplas" <adaplas@pol.net> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 20 10月, 2007 1 次提交
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由 Samuel Thibault 提交于
Some external modules like Speakup need to monitor console output. This adds a VT notifier that such modules can use to get console output events: allocation, deallocation, writes, other updates (cursor position, switch, etc.) [akpm@linux-foundation.org: fix headers_check] Signed-off-by: NSamuel Thibault <samuel.thibault@ens-lyon.org> Cc: Dmitry Torokhov <dtor@mail.ru> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 19 10月, 2007 1 次提交
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由 Jan Engelhardt 提交于
Since default_utf8 is already a sysfs attribute, having an extra CONFIG_VT_UNICODE compile-time option is redundant, since sysfs attributes can be set at boot and run time. Also let Linux VCs default to UTF-8 (as per the discussion at http://lkml.org/lkml/2007/9/6/99). Signed-off-by: NJan Engelhardt <jengelh@computergmbh.de> Cc: Bill Nottingham <notting@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 17 10月, 2007 2 次提交
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由 Bill Nottingham 提交于
As of now, the kernel defaults to non-unicode and XLATE for the keyboard. We've been changing this in Fedora, but that requires patching the defaults in the kernel. The attached introduces CONFIG_VT_UNICODE, which sets the console in unicode mode by default on boot, including both the virtual terminal and the keyboard driver. Signed-off-by: NBill Nottingham <notting@redhat.com> Cc: Samuel Thibault <samuel.thibault@ens-lyon.org> Cc: Dmitry Torokhov <dtor@mail.ru> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Antonino A. Daplas 提交于
Various console drivers are able to resize the screen via the con_resize() hook. This hook is also visible in userspace via the TIOCWINSZ, VT_RESIZE and VT_RESIZEX ioctl's. One particular utility, SVGATextMode, expects that con_resize() of the VGA console will always return success even if the resulting screen is not compatible with the hardware. However, this particular behavior of the VGA console, as reported in Kernel Bugzilla Bug 7513, can cause undefined behavior if the user starts with a console size larger than 80x25. To work around this problem, add an extra parameter to con_resize(). This parameter is ignored by drivers except for vgacon. If this parameter is non-zero, then the resize request came from a VT_RESIZE or VT_RESIZEX ioctl and vgacon will always return success. If this parameter is zero, vgacon will return -EINVAL if the requested size is not compatible with the hardware. The latter is the more correct behavior. With this change, SVGATextMode should still work correctly while in-kernel and stty resize calls can expect correct behavior from vgacon. Signed-off-by: NAntonino Daplas <adaplas@gmail.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 18 7月, 2007 5 次提交
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由 izumi 提交于
VGA console driver can misunderstand the current mode(Text/Graphic) under "disable console blanking" setting. When "disable console blank" is set (blankinterval=0), "do_unblank_screen()" function returns without changing "blank_state", and when "blank_state" is "blank_off", "do_blank_screen() function returns without invoking sw->con_blank() function. That's why VGA console driver can misunderstand the current mode. Signed-off-by: NNobuhiro Tachino <ntachino@redhat.com> Signed-off-by: NTaku Izumi <izumi2005@soft.fujitsu.com> Cc: "Antonino A. Daplas" <adaplas@pol.net> Cc: "Luck, Tony" <tony.luck@intel.com> Acked-by: NPete Zaitcev <zaitcev@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jesse Barnes 提交于
- add comment for unbind_con_driver(). - bind_con_driver() is made private again Signed-off-by: NJesse Barnes <jesse.barnes@intel.com> Signed-off-by: NAntonino Daplas <adaplas@gmail.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Antonino A. Daplas 提交于
Allow fbcon to select the primary display adapter using the fb_is_primary_device() arch-specific helper. If a a primary adapter is detected, fbcon will unbind the old adapter from the VT layer, then rebind using the new adapter. This requires that bind_/unbind_con_driver() be made public. Because this feature may produce unexpected behavior (from the user's POV), this must be explicitly enabled in Kconfig. [akpm@linux-foundation.org: export unbind_con_driver] Signed-off-by: NAntonino Daplas <adaplas@gmail.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jiri Slaby 提交于
vt, use ARRAY_SIZE Signed-off-by: NJiri Slaby <jirislaby@gmail.com> Acked-by: NAlan Cox <alan@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jiri Slaby 提交于
vt, use kzalloc Signed-off-by: NJiri Slaby <jirislaby@gmail.com> Acked-by: NAlan Cox <alan@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 24 6月, 2007 1 次提交
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由 Egmont Koblinger 提交于
Recently my console UTF-8 patch went mainline. Here is an additional patch that fixes two nasty issues and improves a third one, namely: 1. My patch changed the behavior if a glyph is not found in the Unicode mapping table. Previously for Unicode values less than 256 or 512 the kernel tried to display the glyph from that position of the glyph table, which could lead to a different accented letter being displayed. I removed this fallback possibility and changed it to display the replacement symbol. As Behdad pointed out, some fonts (e.g. sun12x22 from the kbd package) lack Unicode mapping information, hence all you get is lots of question marks. Though theoretically it's actually a user-space bug (the font should be fixed), Behdad and I both believe that it'd be good to work around in the kernel by re-introducing the fallback solution for ASCII characters only. This sounds a quite reasonable decision, since all fonts ship the ASCII characters in the first 128 positions. This way users won't be surprised by lots of question marks just because s/he issued a not-so-perfectly parameterized setfont command. As this fallback is only re-introduced for code points below 128, you still won't see an accented letter replaced by another, but at least you'll always get the English letters right. 2. My patch introduced "question mark with inverted color attributes" as a last resort fallback glyph. Though it perfectly works on VGA console, on framebuffer you may end up with question marks that are highlighed but shouldn't be, and normal characters that are accidentally highlighed. This is caused by missing FLUSHes when changing the color attribute. 3. I've updated the table of double-width character based on Markus's updated version. Only ten new code poings (one interval) is added. Signed-off-by: NEgmont Koblinger <egmont@uhulinux.hu> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 09 5月, 2007 5 次提交
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由 Matthias Kaehlcke 提交于
The virtual console driver uses a semaphore as mutex. Use the mutex API instead of the (binary) semaphore. Signed-off-by: NMatthias Kaehlcke <matthias.kaehlcke@gmail.com> Cc: "Antonino A. Daplas" <adaplas@pol.net> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Antonino A. Daplas 提交于
Create a variable, default_utf8, that defines the system-wide default UTF-8 setting. This variable can be altered via sysfs. If the variable is properly set, this should mimimize breakage of UTF-8 encoded consoles when doing a reset or echo -e '\033c' and of newly opened/allocated consoles. This is based from patches by Jan Engelhardt and Paul LeoNerd Evans. Signed-off-by: NAntonino Daplas <adaplas@gmail.com> Cc: Jan Engelhardt <jengelh@linux01.gwdg.de> Cc: Paul LeoNerd Evans <leonerd@leonerd.org.uk> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jan Engelhardt 提交于
Add color support to the "underline" and "italic" attributes as in OpenBSD/NetBSD-style (vt220) and xterm. Signed-off-by: NJan Engelhardt <jengelh@gmx.de> Acked-by: N"Antonino A. Daplas" <adaplas@pol.net> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jan Engelhardt 提交于
Allow for the palette to be exposed and changed via sysfs. A call to /usr/bin/reset will slurp the new definitions in for the current console. Already posted at http://lkml.org/lkml/2006/1/15/149Signed-off-by: NJan Engelhardt <jengelh@gmx.de> Cc: "Antonino A. Daplas" <adaplas@pol.net> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Egmont Koblinger 提交于
The UTF-8 part of the vt driver suffers from the following issues which are addressed in my patch: 1) If there's no glyph found for a particular valid UTF-8 character, we try to display U+FFFD. However if this one is not found either, here's what the current kernel does: - First, if the Unicode value is less than the number of glyphs, use the glyph directly from that position of the glyph table. While it may be a good idea in the 8-bit world, it has absolutely no sense with Unicode in mind. For example, if a Latin-2 font is loaded and an application prints U+00FB ("u with circumflex", not present in Latin-2) then as a fallback solution the glyph from the 0xFB position of the Latin-2 fontset (which is an "u with double accent" - a different character) is displayed. - Second, if this fallback fails too, a simple ASCII question mark is printed, which is visually undistinguishable from a real question mark. I changed the code to skip the first step (except if in non-UTF-8 mode), and changed the second step to print the question mark with inverse color attributes, so it is visually clear that it's not a real question mark, and resembles more to the common glyph of U+FFFD. 2) The UTF-8 decoder is buggy in many ways: - Lone continuation bytes (section 3.1 of Markus Kuhn's UTF-8 stress test) are not caught, they are displayed as some "random" (taken directly form the font table, see above) glyphs instead the replacement character. - Incomplete sequences (sections 3.2 and 3.3 of the stress test) emit no replacement character, but rather cause the subsequent valid character to be displayed more times(!). - The decoder is not safe: overlong sequences are not caught currently, they are displayed as if these were valid representations. This may even have security impacts. - The decoder does not handle D800..DFFF and FFFE..FFFF specially, it just emits these code points and lets it be looked up in the glyph table. Since these are invalid code points, I replace them by U+FFFD and hence give no chance for them to be looked up in the glyph table. (Assuming no font ships glyphs for these code points, this change is not visible to the users since the glyph shown will be the same.) With my fixes to the decoder it now behaves exactly as Markus Kuhn's stress test recommends. 3) It has no concept of double-width (CJK) characters. It's way beyond the scope of my patch to try to display them, but at least I think it's important for the cursor to jump two positions when printing such characters, since this is what applications (such as text editors) expect. Currently the cursor only jumps one position, and hence applications suffer from displaying and refreshing problems, and editing some English letters that are preceded by some CJK characters in the same line is a nightmare. With my patch an additional space is inserted after the CJK character has been printed (which usually means a replacement symbol of course). (If U+FFFD isn't availble and hence an inverse question mark is displayed in the first cell, I keep the inverted state for the space in the 2nd column so it's quite easy to see that they are tied together.) 4) There is a small built-in table of zero-width spaces that are not to be printed but silently skipped. U+200A is included there, but it's not a zero-width character, so I remove it from there. Signed-off-by: NEgmont Koblinger <egmont@uhulinux.hu> Cc: Jan Engelhardt <jengelh@linux01.gwdg.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: "Antonino A. Daplas" <adaplas@pol.net> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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