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There's a bunch of folks who're trying to make printk less
contended and faster, but there's a problem: printk uses the
console_lock, and the console lock has become the BKL for all things
fbdev/fbcon, which in turn pulled in half the drm subsystem under that
lock. That's awkward.
There reasons for that is probably just a historical accident:
- fbcon is a runtime option of fbdev, i.e. at runtime you can pick
whether your fbdev driver instances are used as kernel consoles.
Unfortunately this wasn't implemented with some module option, but
through some module loading magic: As long as you don't load
fbcon.ko, there's no fbdev console support, but loading it (in any
order wrt fbdev drivers) will create console instances for all fbdev
drivers.
- This was implemented through a notifier chain. fbcon.ko enumerates
all fbdev instances at load time and also registers itself as
listener in the fbdev notifier. The fbdev core tries to register new
fbdev instances with fbcon using the notifier.
- On top of that the modifier chain is also used at runtime by the
fbdev subsystem to e.g. control backlights for panels.
- The problem is that the notifier puts a mutex locking context
between fbdev and fbcon, which mixes up the locking contexts for
both the runtime usage and the register time usage to notify fbcon.
And at runtime fbcon (through the fbdev core) might call into the
notifier from a printk critical section while console_lock is held.
- This means console_lock must be an outer lock for the entire fbdev
subsystem, which also means it must be acquired when registering a
new framebuffer driver as the outermost lock since we might call
into fbcon (through the notifier) which would result in a locking
inversion if fbcon would acquire the console_lock from its notifier
callback (which it needs to register the console).
- console_lock can be held anywhere, since printk can be called
anywhere, and through the above story, plus drm/kms being an fbdev
driver, we pull in a shocking amount of locking hiercharchy
underneath the console_lock. Which makes cleaning up printk really
hard (not even splitting console_lock into an rwsem is all that
useful due to this).
There's various ways to address this, but the cleanest would be to
make fbcon a compile-time option, where fbdev directly calls the fbcon
register functions from register_framebuffer, or dummy static inline
versions if fbcon is disabled. Maybe augmented with a runtime knob to
disable fbcon, if that's needed (for debugging perhaps).
But this could break some users who rely on the magic "loading
fbcon.ko enables/disables fbdev framebuffers at runtime" thing, even
if that's unlikely. Hence we must be careful:
1. Create a compile-time dependency between fbcon and fbdev in the
least minimal way. This is what this patch does.
2. Wait at least 1 year to give possible users time to scream about
how we broke their setup. Unlikely, since all distros make fbcon
compile-in, and embedded platforms only compile stuff they know they
need anyway. But still.
3. Convert the notifier to direct functions calls, with dummy static
inlines if fbcon is disabled. We'll still need the fb notifier for the
other uses (like backlights), but we can probably move it into the fb
core (atm it must be built-into vmlinux).
4. Push console_lock down the call-chain, until it is down in
console_register again.
5. Finally start to clean up and rework the printk/console locking.
For context of this saga see
commit 50e244cc793d511b86adea24972f3a7264cae114
Author: Alan Cox <alan@linux.intel.com>
Date: Fri Jan 25 10:28:15 2013 +1000
fb: rework locking to fix lock ordering on takeover
plus the pile of commits on top that tried to make this all work
without terminally upsetting lockdep. We've uncovered all this when
console_lock lockdep annotations where added in
commit daee779718a319ff9f83e1ba3339334ac650bb22
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Sat Sep 22 19:52:11 2012 +0200
console: implement lockdep support for console_lock
On the patch itself:
- Switch CONFIG_FRAMEBUFFER_CONSOLE to be a boolean, using the overall
CONFIG_FB tristate to decided whether it should be a module or
built-in.
- At first I thought I could force the build depency with just a dummy
symbol that fbcon.ko exports and fb.ko uses. But that leads to a
module depency cycle (it works fine when built-in).
Since this tight binding is the entire goal the simplest solution is
to move all the fbcon modules (and there's a bunch of optinal
source-files which are each modules of their own, for no good
reason) into the overall fb.ko core module. That's a bit more than
what I would have liked to do in this patch, but oh well.
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
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The framebuffer code uses the current background color to fill the border
when switching consoles, however, this results in inconsistent behavior.
For example:
- start Midnigh Commander
- the border is black
- switch to another console and switch back
- the border is cyan
- type something into the command line in mc
- the border is cyan
- switch to another console and switch back
- the border is black
- press F9 to go to menu
- the border is black
- switch to another console and switch back
- the border is dark blue
When switching to a console with Midnight Commander, the border is random
color that was left selected by the slang subsystem.
This patch fixes this inconsistency by always using black as the
background color when switching consoles.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
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Switch to kmalloc(,GFP_ATOMIC) in bit_putcs to fix below trace:
[ 9.771812] BUG: sleeping function called from invalid context at /usr/src/linux-git/mm/slub.c:943
[ 9.771814] in_atomic(): 1, irqs_disabled(): 1, pid: 1063, name: mount
[ 9.771818] Pid: 1063, comm: mount Not tainted 3.5.0-jupiter-00003-g8d858b1-dirty #2
[ 9.771819] Call Trace:
[ 9.771838] [<c104f79b>] __might_sleep+0xcb/0xe0
[ 9.771844] [<c10c00d4>] __kmalloc+0xb4/0x1c0
[ 9.771851] [<c1041d4a>] ? queue_work+0x1a/0x30
[ 9.771854] [<c1041dcf>] ? queue_delayed_work+0xf/0x30
[ 9.771862] [<c1205832>] ? bit_putcs+0xf2/0x3e0
[ 9.771865] [<c1041e01>] ? schedule_delayed_work+0x11/0x20
[ 9.771868] [<c1205832>] bit_putcs+0xf2/0x3e0
[ 9.771875] [<c12002b8>] ? get_color.clone.14+0x28/0x100
[ 9.771878] [<c1200d2f>] fbcon_putcs+0x11f/0x130
[ 9.771882] [<c1205740>] ? bit_clear+0xe0/0xe0
[ 9.771885] [<c1200f6d>] fbcon_redraw.clone.21+0x11d/0x160
[ 9.771889] [<c120383d>] fbcon_scroll+0x79d/0xe10
[ 9.771892] [<c12002b8>] ? get_color.clone.14+0x28/0x100
[ 9.771897] [<c124c0b4>] scrup+0x64/0xd0
[ 9.771900] [<c124c22b>] lf+0x2b/0x60
[ 9.771903] [<c124cc95>] vt_console_print+0x1d5/0x2f0
[ 9.771907] [<c124cac0>] ? register_vt_notifier+0x20/0x20
[ 9.771913] [<c102b335>] call_console_drivers.clone.5+0xa5/0xc0
[ 9.771916] [<c102c58e>] console_unlock+0x2fe/0x3c0
[ 9.771920] [<c102ca16>] vprintk_emit+0x2e6/0x300
[ 9.771924] [<c13f01ae>] printk+0x38/0x3a
[ 9.771931] [<c112e8fe>] reiserfs_remount+0x2ae/0x3e0
[ 9.771934] [<c112e650>] ? reiserfs_fill_super+0xb00/0xb00
[ 9.771939] [<c10ca0ab>] do_remount_sb+0xab/0x150
[ 9.771943] [<c1034476>] ? ns_capable+0x46/0x70
[ 9.771948] [<c10e059c>] do_mount+0x20c/0x6b0
[ 9.771955] [<c10a7044>] ? strndup_user+0x34/0x50
[ 9.771958] [<c10e0acc>] sys_mount+0x6c/0xa0
[ 9.771964] [<c13f2557>] sysenter_do_call+0x12/0x26
According to comment in bit_putcs() that kammloc() call only happens
when fbcon is drawing to a monochrome framebuffer (which is my case with
hid-picolcd).
Signed-off-by: Bruno Prémont <bonbons@linux-vserver.org>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
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This patch uninlines four similar functions, foo_update_attr(), in four
fbcon-related files.
These functions contain loops, two of theam have _nested_ loops, and they
have more than one callsite each. I think they should not be inlined.
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
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Use DIV_ROUND_UP explicitly instead of manual shifts and adds. It makes
the code more readable and consistent (sometimes there were shifts,
sometimes divs).
There is no change on the assembly level (compilers should do the right
job).
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The current attr_fgcol_ec / attr_bgcol_ec macros do a simple shift of bits
to get the color from vc_video_erase_char. For a monochrome display
however the attribute does not contain any color, only attribute bits.
Furthermore the reverse bit is lost because it is shifted out, the
resulting color is always 0.
This can bee seen on a monochrome console either directly or by setting it
to inverse mode via "setterm -inversescreen on" . Text is written with
correct color, fb_fillrects from a bit_clear / bit_clear_margins will get
wrong colors.
Signed-off-by: Thomas Pfaff <tpfaff@pcs.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
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Do not pass the structure display since fbcon is already keeping the pointer
to the current display.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This patch series implements generic code to rotate the console at 90, 180,
and 270 degrees. The implementation is completely done in the framebuffer
console level, thus no changes to the framebuffer layer or to the drivers
are needed.
Console rotation is required by some Sharp-based devices where the natural
orientation of the display is not at 0 degrees. Also, users that have
displays that can pivot will benefit by having a console in portrait mode
if they so desire.
The choice to implement the code in the console layer rather than in the
framebuffer layer is due to the following reasons:
- it's fast
- it does not require driver changes
- it can coexist with devices that can rotate the display at the hardware level
- it complements graphics applications that can do display rotation
The changes to core fbcon are minimal-- recognition of the console
rotation angle so it can swap directions, origins and axes (xres vs yres,
xpanstep vs ypanstep, xoffset vs yoffset, etc) and storage of the rotation
angle per display. The bulk of the code that does the actual drawing to the
screen are placed in separate files. Each angle of rotation has separate
methods (bmove, clear, putcs, cursor, update_start which is derived from
update_var, and clear_margins). To mimimize processing time, the fontdata
are pre-rotated at each console switch (only if the font or the angle has
changed).
The option can be compiled out (CONFIG_FRAMEBUFFER_CONSOLE_ROTATION = n) if
rotation is not needed.
Choosing the rotation angle can be done in several ways:
1. boot option fbcon=rotate:n, where
n = 0 - normal
n = 1 - 90 degrees (clockwise)
n = 2 - 180 degrees (upside down)
n = 3 - 270 degrees (counterclockwise)
2. echo n > /sys/class/graphics/fb[num]/con_rotate
where n is the same as described above. It sets the angle of rotation
of the current console
3 echo n > /sys/class/graphics/fb[num]/con_rotate_all
where n is the same as described above. Globally sets the angle of
rotation.
GOTCHAS:
The option, especially at angles of 90 and 270 degrees, will exercise
the least used code of drivers. Namely, at these angles, panning is done
in the x-axis, so it can reveal bugs in the driver if xpanstep is set
incorrectly. A workaround is to set xpanstep = 0.
Secondly, at these angles, the framebuffer memory access can be
unaligned if (fontheight * bpp) % 32 ~= 0 which can reveal bugs in the drivers
imageblit, fillrect and copyarea functions. (I think cfbfillrect may have
this buglet). A workaround is to use a standard 8x16 font.
Speed:
The scrolling speed difference between 0 and 180 degrees is minimal,
somewhere areound 1-2%. At 90 or 270 degress, speed drops down to a vicinity
of 30-40%. This is understandable because the blit direction is across the
framebuffer "direction." Scrolling will be helped at these angles if xpanstep
is not equal to zero, use of 8x16 fonts, and setting xres_virtual >= xres * 2.
Note: The code is tested on little-endian only, so I don't know if it will
work in big-endian. Please let me know, it will take only less than a minute
of your time.
This patch prepares fbcon for console rotation and contains the following
changes:
- add rotate field in struct fbcon_ops to keep fbcon's current rotation
angle
- add con_rotate field in struct display to store per-display rotation angle
- create a private copy of the current var to fbcon. This will prevent
fbcon from directly manipulating info->var, especially the fields xoffset,
yoffset and vmode.
- add ability to swap pertinent axes (xres, yres; xpanstep, ypanstep; etc)
depending on the rotation angle
- change global update_var() (function that sets the screen start address)
as an fbcon method update_start. This is required because the axes, start
offset, and/or direction can be reversed depending on the rotation angle.
- add fbcon method rotate_font() which will rotate each character bitmap to
the correct angle of rotation.
- add fbcon boot option 'rotate' to select the angle of rotation at bootime.
Currently does nothing until all patches are applied.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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According to Jon Smirl, filling in the field fb_cursor with soft_cursor for
drivers that do not support hardware cursors is redundant. The soft_cursor
function is usable by all drivers because it is just a wrapper around
fb_imageblit. And because soft_cursor is an fbcon-specific hook, the file is
moved to the console directory.
Thus, drivers that do not support hardware cursors can leave the fb_cursor
field blank. For drivers that do, they can fill up this field with their own
version.
The end result is a smaller code size. And if the framebuffer console is not
loaded, module/kernel size is also reduced because the soft_cursor module will
also not be loaded.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The function bit_putcs() in drivers/video/console/bitblit.c is becoming large.
Break it up into its component functions (bit_putcs_unaligned and
bit_putcs_aligned).
Incorporated fb_pad_aligned_buffer() optimization by Roman Zippel.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This trivial patch gives a performance boost to the framebuffer console
Constructing the bitmaps that are given to the bitblit functions of the
framebuffer drivers is time consuming. Here we avoide a call to the slow
fb_pad_aligned_buffer(). The patch replaces that call with a simple but
much more efficient bytewise copy.
The kernel spends a significant time at this place if you use 8x* fonts.
Every pixel displayed on your screen is prepared here.
Some benchmark results:
Displaying a file of 2000 lines with 160 characters each takes 889 ms
system time using cyblafb on my system (I´m using a 1280x1024 video mode,
resulting in a 160x64 character console)
Displaying the same file with the enclosed patch applied to 2.6.13 only
takes 760 ms system time, saving 129 ms or 14.5%.
Font widths other than 8 are not affected.
The advantage and correctness of this patch should be obvious.
Signed-off-by: Knut Petersen <Knut_Petersen@t-online.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Currently, fbcon assumes that the visual FB_VISUAL_MONO* is always 1 bit.
According to Geert, there are old hardware where it's possible to have
monochrome at 8-bit, but has only 2 colors, black - 0x00 and white - 0xff.
Fix color handlers (fb_get_color_depth, and get_color) for this special case.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Shrink the stack when calling the drawing alignment functions.
Signed-off-by: James Simmons <jsimmons@www.infradead.org>
Cc: "Antonino A. Daplas" <adaplas@hotpop.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Since no one is using the inbuf, outbuf of struct fb_pixmap I removed their
use in the framebuffer console. The idea is instead move the pixmap
functionality below the accelerated functions intead of on top as the way
it is now. If there is no objection please apply. This is against Linus
latestr GIT tree. Thank you.
Signed-off-by: James Simmons <jsimmons@www.infradead.org>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
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