linux-stable/drivers/video/console/Kconfig

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# SPDX-License-Identifier: GPL-2.0-only
#
# Video configuration
#
menu "Console display driver support"
config VGA_CONSOLE
bool "VGA text console" if EXPERT || !X86
depends on !4xx && !PPC_8xx && !SPARC && !M68K && !PARISC && !SUPERH && \
(!ARM || ARCH_FOOTBRIDGE || ARCH_INTEGRATOR || ARCH_NETWINDER) && \
!ARM64 && !ARC && !MICROBLAZE && !OPENRISC && !S390 && !UML
select APERTURE_HELPERS if (DRM || FB || VFIO_PCI_CORE)
default y
help
Saying Y here will allow you to use Linux in text mode through a
display that complies with the generic VGA standard. Virtually
everyone wants that.
The program SVGATextMode can be used to utilize SVGA video cards to
their full potential in text mode. Download it from
<ftp://ibiblio.org/pub/Linux/utils/console/>.
Say Y.
config MDA_CONSOLE
depends on !M68K && !PARISC && ISA
tristate "MDA text console (dual-headed)"
help
Say Y here if you have an old MDA or monochrome Hercules graphics
adapter in your system acting as a second head ( = video card). You
will then be able to use two monitors with your Linux system. Do not
say Y here if your MDA card is the primary card in your system; the
normal VGA driver will handle it.
To compile this driver as a module, choose M here: the
module will be called mdacon.
If unsure, say N.
config SGI_NEWPORT_CONSOLE
tristate "SGI Newport Console support"
depends on SGI_IP22 && HAS_IOMEM
select FONT_SUPPORT
help
Say Y here if you want the console on the Newport aka XL graphics
card of your Indy. Most people say Y here.
config DUMMY_CONSOLE
bool
default y
config DUMMY_CONSOLE_COLUMNS
int "Initial number of console screen columns"
depends on DUMMY_CONSOLE && !ARM
default 160 if PARISC
default 80
help
On PA-RISC, the default value is 160, which should fit a 1280x1024
monitor.
Select 80 if you use a 640x480 resolution by default.
config DUMMY_CONSOLE_ROWS
int "Initial number of console screen rows"
depends on DUMMY_CONSOLE && !ARM
default 64 if PARISC
default 25
help
On PA-RISC, the default value is 64, which should fit a 1280x1024
monitor.
Select 25 if you use a 640x480 resolution by default.
config FRAMEBUFFER_CONSOLE
fbcon: Make fbcon a built-time depency for fbdev 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>
2017-08-01 15:32:07 +00:00
bool "Framebuffer Console support"
depends on FB && !UML
select VT_HW_CONSOLE_BINDING
select CRC32
select FONT_SUPPORT
help
Low-level framebuffer-based console driver.
config FRAMEBUFFER_CONSOLE_LEGACY_ACCELERATION
bool "Enable legacy fbcon hardware acceleration code"
depends on FRAMEBUFFER_CONSOLE
default y if PARISC
default n
help
This option enables the fbcon (framebuffer text-based) hardware
acceleration for graphics drivers which were written for the fbdev
graphics interface.
On modern machines, on mainstream machines (like x86-64) or when
using a modern Linux distribution those fbdev drivers usually aren't used.
So enabling this option wouldn't have any effect, which is why you want
to disable this option on such newer machines.
If you compile this kernel for older machines which still require the
fbdev drivers, you may want to say Y.
If unsure, select n.
config FRAMEBUFFER_CONSOLE_DETECT_PRIMARY
bool "Map the console to the primary display device"
depends on FRAMEBUFFER_CONSOLE
default n
help
If this option is selected, the framebuffer console will
automatically select the primary display device (if the architecture
supports this feature). Otherwise, the framebuffer console will
always select the first framebuffer driver that is loaded. The latter
is the default behavior.
You can always override the automatic selection of the primary device
by using the fbcon=map: boot option.
If unsure, select n.
[PATCH] fbcon: Console Rotation - Prepare fbcon for console rotation 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>
2005-11-09 05:39:09 +00:00
config FRAMEBUFFER_CONSOLE_ROTATION
bool "Framebuffer Console Rotation"
depends on FRAMEBUFFER_CONSOLE
help
Enable display rotation for the framebuffer console. This is done
in software and may be significantly slower than a normally oriented
display. Note that the rotation is done at the console level only
such that other users of the framebuffer will remain normally
oriented.
[PATCH] fbcon: Console Rotation - Prepare fbcon for console rotation 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>
2005-11-09 05:39:09 +00:00
config FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER
bool "Framebuffer Console Deferred Takeover"
depends on FB=y && FRAMEBUFFER_CONSOLE && DUMMY_CONSOLE
help
If enabled this defers the framebuffer console taking over the
console from the dummy console until the first text is displayed on
the console. This is useful in combination with the "quiet" kernel
commandline option to keep the framebuffer contents initially put up
by the firmware in place, rather then replacing the contents with a
black screen as soon as fbcon loads.
config STI_CONSOLE
bool "STI text console"
depends on PARISC && HAS_IOMEM
select FONT_SUPPORT
select CRC32
default y
help
The STI console is the builtin display/keyboard on HP-PARISC
machines. Say Y here to build support for it into your kernel.
The alternative is to use your primary serial port as a console.
endmenu