It was only used by the panic support in fbcon, which is now gone.
Remove this now dead code too.
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Joe Perches <joe@perches.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Meng Xu <mengxu.gatech@gmail.com>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Thomas Meyer <thomas@m3y3r.de>
Cc: Mike Frysinger <vapier@chromium.org>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Thierry Reding <treding@nvidia.com>
Cc: David Lechner <david@lechnology.com>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180822085405.10787-2-daniel.vetter@ffwll.ch
This was only added for the drm's fbdev emulation support, so that it
would try harder to show the Oops.
Unfortunately this never really worked reliably, and in practice ended
up pushing the real Oops off the screen due to plentyfull locking,
sleep-while-atomic and other issues. So we removed all that support
from the fbdev emulation a while back. Aside: We've also removed the
kgdb support, for similar reasons.
Since it's such a small patch I figured I don't split this up into the
usual 3-phase removal.
Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Alexander Kapshuk <alexander.kapshuk@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Thierry Reding <treding@nvidia.com>
Cc: David Lechner <david@lechnology.com>
Cc: nouveau@lists.freedesktop.org
Cc: linux-fbdev@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180822085405.10787-1-daniel.vetter@ffwll.ch
Taking over the console involves allocating mem with GFP_KERNEL, talking
to drm drivers, etc. So this should not be done from an atomic context.
But the console-output trigger deferred console takeover may happen from an
atomic context, which leads to "BUG: sleeping function called from invalid
context" errors.
This commit fixes these errors by doing the deferred takeover from a
workqueue.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
[b.zolnierkie: remove unused variable]
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
We rely on dummycon's output notifier mechanism to defer the takeover.
If say vgacon is the current console driver then dummycon will never get
used so its output notifier will also never get called and fbcon never
takes over. This commit fixes this by only deferring the console takeover
if the current console driver is the dummycon driver.
This commit also moves the entirety of fbcon_start under the console_lock,
since the conswitchp which fbcon_start now checks is protected by it.
This commit also inlines fbcon_register_output_notifier, since we now
need a #ifdef CONFIG_FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER in fbcon_start
anyways because of the write access to the deferred_takeover variable,
this has the added advantage that it puts the
dummycon_register_output_notifier() call directly after the "conswitchp !=
&dummy_con" comparison making it clear why that check is there.
Note the arch setup code will set conswitchp to either dummy_con or
vga_con, in the cases where it gets set to vga_con even though their is
no vga_con present we rely on vga_con_startup() to set conswitchp to
dummy_con. vga_con_startup() is guaranteed to happen before
fb_console_init() as it gets called as a console_initcall where as
fb_console_init() gets called as a subsys_initcall.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Following pattern is often used:
for (i = 0; i < FB_MAX; i++) {
if (registered_fb[i]) {
...
}
}
Therefore, as Andy's suggestion, for_each_registered_fb() helper can
be introduced to make the code easier to read and write by reducing
indentation level. It also saves few lines of code in each occurrence.
This patch convert all part here at the same time.
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Yisheng Xie <ysxie@foxmail.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: David Lechner <david@lechnology.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Currently fbcon claims fbdevs as soon as they are registered and takes over
the console as soon as the first fbdev gets registered.
This behavior is undesirable in cases where a smooth graphical bootup is
desired, in such cases we typically want the contents of the framebuffer
(typically a vendor logo) to stay in place as is.
The current solution for this problem (on embedded systems) is to not
enable fbcon.
This commit adds a new FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER config option,
which when enabled defers fbcon taking over the console from the dummy
console until the first text is displayed on the console. Together with the
"quiet" kernel commandline option, this allows fbcon to still be used
together with a smooth graphical bootup, having it take over the console as
soon as e.g. an error message is logged.
Note the choice to detect the first console output in the dummycon driver,
rather then handling this entirely inside the fbcon code, was made after
2 failed attempts to handle this entirely inside the fbcon code. The fbcon
code is woven quite tightly into the console code, making this to only
feasible option.
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Replace comments about places where the console lock should be held with
calls to WARN_CONSOLE_UNLOCKED() to assert that it is actually held.
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
This expands the no-op dummy functions into full prototypes to avoid
indirect call mismatches when running under Control Flow Integrity
checking, like with Clang's -fsanitize=cfi.
Co-Developed-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
On some hardware the LCD panel is not mounted upright in the casing,
but upside-down or rotated 90 degrees. In this case we want the console
to automatically be rotated to compensate.
The fbdev-driver may know about the need to rotate. Add a new
fbcon_rotate_hint field to struct fb_info, which gets initialized to -1.
If the fbdev-driver knows that some sort of rotation is necessary then
it can set this field to a FB_ROTATE_* value to tell the fbcon console
driver to rotate the console.
Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171125193553.23986-2-hdegoede@redhat.com
During console takeover, which happens for all DRM/KMS setups using the
fbdev helpers, fbcon_startup() is called before fbcon_init() and as a
result con2fb_acquire_newinfo() will not be called (info->fbcon_par was
set to non-NULL in fbcon_startup()) to assign ops->info.
This causes the cursor_timer_handler() to unreference a NULL pointer.
Avoid this by unconditionally assigning ops->info during fbcon_startup()
so that it will be available early, but keep the additional assignment
in con2fb_acquire_newinfo() to support console remapping at runtime.
Signed-off-by: Thierry Reding <treding@nvidia.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly. One tracking pointer was added.
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: David Lechner <david@lechnology.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Jean Delvare <jdelvare@suse.de>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
[b.zolnierkie: ported it over pxa3xx_gcu changes]
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
This removes the restriction on the value range of the fbcon=margin:
parameter. The color value really depends on the driver being used.
Signed-off-by: David Lechner <david@lechnology.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
[b.zolnierkie: ported over fbcon changes]
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
This adds a new command line option to select the fbcon margin color.
The motivation for this is screens where black does not blend into the
physical surroundings of the screen. For example, using an LCD (not the
backlit kind), white text on a black background is hard to read, so
inverting the colors is preferred. However, when you do this, most of the
screen is filled with white but the margins are still filled with black.
This makes a big, black, backwards 'L' on the screen. By setting
fbcon=margin:7, the margins will be filled with white and the LCD looks as
expected.
Signed-off-by: David Lechner <david@lechnology.com>
[b.zolnierkie: ported over fbcon changes]
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Some x86 clamshell design devices use portrait tablet screens and a
display engine which cannot rotate in hardware, so we need to rotate
the fbcon to compensate.
This commit adds a DMI based quirk table which is initially populated with
4 such devices: The Asus T100HA, GPD Pocket, the GPD win and the I.T.Works
TW891, so that the console comes up in the right orientation on these
devices OOTB.
Unfortunately these (cheap) devices also typically have quite generic DMI
data, so we match on a combination of DMI data, screen resolution and a
list of known BIOS dates to avoid false positives.
Suggested-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
[b.zolnierkie: ported over fbcon changes]
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Instead check info->ops->owner, which amounts to the same.
Spotted because I want to remove the pile of broken and cargo-culted
fb_info->flags assignments in drm drivers.
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
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 50e244cc79
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 daee779718
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>
Daniel Vetter