Rendering calls may be done simultaneously from the workqueue,
dlfb_ops_write, dlfb_ops_ioctl, dlfb_ops_set_par and dlfb_dpy_deferred_io.
The code is robust enough so that it won't crash on concurrent rendering.
However, concurrent rendering may cause display corruption if the same
pixel is simultaneously being rendered. In order to avoid this corruption,
this patch adds a mutex around the rendering calls.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: Bernie Thompson <bernie@plugable.com>
Cc: Ladislav Michl <ladis@linux-mips.org>
Cc: <stable@vger.kernel.org>
[b.zolnierkie: replace "dlfb:" with "uldfb:" in the patch summary]
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
If a framebuffer device is used as a console, the rendering calls
(copyarea, fillrect, imageblit) may be done with the console spinlock
held. On udlfb, these function call dlfb_handle_damage that takes a
blocking semaphore before acquiring an URB.
In order to fix the bug, this patch changes the calls copyarea, fillrect
and imageblit to offload USB work to a workqueue.
A side effect of this patch is 3x improvement in console scrolling speed
because the device doesn't have to be updated after each copyarea call.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: Bernie Thompson <bernie@plugable.com>
Cc: Ladislav Michl <ladis@linux-mips.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
In the current kernel, then kzalloc() can't fail for small allocations,
but if it did fail then we would have a NULL dereference in the error
handling. Also in dlfb_usb_disconnect() if "info" were NULL then it
would cause an Oops inside the unregister_framebuffer() function but it
can't be NULL so let's remove that check.
Fixes: 68a958a915 ("udlfb: handle unplug properly")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Bernie Thompson <bernie@plugable.com>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Alexey Khoroshilov <khoroshilov@ispras.ru>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Wen Yang <wen.yang99@zte.com.cn>
[b.zolnierkie: added "Fixes:" tag]
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
The udlfb driver maintained an open count and cleaned up itself when the
count reached zero. But the console is also counted in the reference count
- so, if the user unplugged the device, the open count would not drop to
zero and the driver stayed loaded with console attached. If the user
re-plugged the adapter, it would create a device /dev/fb1, show green
screen and the access to the console would be lost.
The framebuffer subsystem has reference counting on its own - in order to
fix the unplug bug, we rely the framebuffer reference counting. When the
user unplugs the adapter, we call unregister_framebuffer unconditionally.
unregister_framebuffer will unbind the console, wait until all users stop
using the framebuffer and then call the fb_destroy method. The fb_destroy
cleans up the USB driver.
This patch makes the following changes:
* Drop dlfb->kref and rely on implicit framebuffer reference counting
instead.
* dlfb_usb_disconnect calls unregister_framebuffer, the rest of driver
cleanup is done in the function dlfb_ops_destroy. dlfb_ops_destroy will
be called by the framebuffer subsystem when no processes have the
framebuffer open or mapped.
* We don't use workqueue during initialization, but initialize directly
from dlfb_usb_probe. The workqueue could race with dlfb_usb_disconnect
and this racing would produce various kinds of memory corruption.
* We use usb_get_dev and usb_put_dev to make sure that the USB subsystem
doesn't free the device under us.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
cc: Dave Airlie <airlied@redhat.com>
Cc: Bernie Thompson <bernie@plugable.com>,
Cc: Ladislav Michl <ladis@linux-mips.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
spin_lock_irqsave and spin_unlock_irqrestore is inteded to be called from
a context where it is unknown if interrupts are enabled or disabled (such
as interrupt handlers). From a process context, we should call
spin_lock_irq and spin_unlock_irq, that avoids the costly pushf and popf
instructions.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Modern processors can detect linear memory accesses and prefetch data
automatically, so there's no need to use prefetch.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Currently, the udlfb driver only tests for identical bytes at the
beginning or at the end of a page and renders anything between the first
and last mismatching pixel. But pages are not the same as lines, so this
is quite suboptimal - if there is something modified at the beginning of a
page and at the end of a page, the whole page is rendered, even if most of
the page is not modified.
This patch makes it test for identical pixels at the beginning and end of
each rendering command. This patch improves identical byte detection by
41% when playing video in a window.
This patch also fixes a possible screen corruption if the user is writing
to the framebuffer while dlfb_render_hline is in progress - the pixel data
that is copied to the backbuffer with memcpy may be different from the
pixel data that is actually rendered to the hardware (because the content
of the framebuffer may change between memcpy and the rendering command).
We must make sure that we copy exactly the same pixel as the pixel that is
being rendered.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
[b.zolnierkie: fix code indent]
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
This patch changes udlfb so that it may reallocate the framebuffer when
setting higher-resolution mode. If we boot the system without monitor
attached, udlfb creates a framebuffer with the size 800x600. This patch
makes it possible to select higher videomode with the fbset command when
a monitor is attached.
Note that there is no reliable way to prevent the system from touching the
old framebuffer, so we must not free it. We add it to the list
dlfb->deferred_free and free it when the driver is unloaded.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
[b.zolnierkie: sparse fixes]
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Set the variable "line_length" in the function dlfb_ops_set_par. Without
this, we get garbage if we select different videomode with fbset.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Allocations larger than PAGE_ALLOC_COSTLY_ORDER are unreliable and they
may fail anytime. This patch fixes the udlfb driver so that when a large
alloactions fails, it tries to do multiple smaller allocations.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
The defio subsystem overwrites the method fb_osp->mmap. That method is
stored in module's static data - and that means that if we have multiple
diplaylink adapters, they will over write each other's method.
In order to avoid interference between multiple adapters, we copy the
fb_ops structure to a device-local memory.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
The udlfb driver reprograms the hardware everytime the user switches the
console, that makes quite unusable when working on the console.
This patch makes the driver remember the videomode we are in and avoid
reprogramming the hardware if we switch to the same videomode.
We mask the "activate" field and the "FB_VMODE_SMOOTH_XPAN" flag when
comparing the videomode, because they cause spurious switches when
switching to and from the Xserver.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
The displaylink hardware has such a peculiarity that it doesn't render a
command until next command is received. This produces occasional
corruption, such as when setting 22x11 font on the console, only the first
line of the cursor will be blinking if the cursor is located at some
specific columns.
When we end up with a repeating pixel, the driver has a bug that it leaves
one uninitialized byte after the command (and this byte is enough to flush
the command and render it - thus it fixes the screen corruption), however
whe we end up with a non-repeating pixel, there is no byte appended and
this results in temporary screen corruption.
This patch fixes the screen corruption by always appending a byte 0xAF at
the end of URB. It also removes the uninitialized byte.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
I observed that the performance of the udl fb driver degrades over time.
On a freshly booted machine, it takes 6 seconds to do "ls -la /usr/bin";
after some time of use, the same operation takes 14 seconds.
The reason is that the value of "limit_sem" decays over time.
The udl driver uses a semaphore "limit_set" to specify how many free urbs
are there on dlfb->urbs.list. If the count is zero, the "down" operation
will sleep until some urbs are added to the freelist.
In order to avoid some hypothetical deadlock, the driver will not call
"up" immediately, but it will offload it to a workqueue. The problem is
that if we call "schedule_delayed_work" on the same work item multiple
times, the work item may only be executed once.
This is happening:
* some urb completes
* dlfb_urb_completion adds it to the free list
* dlfb_urb_completion calls schedule_delayed_work to schedule the function
dlfb_release_urb_work to increase the semaphore count
* as the urb is on the free list, some other task grabs it and submits it
* the submitted urb completes, dlfb_urb_completion is called again
* dlfb_urb_completion calls schedule_delayed_work, but the work is already
scheduled, so it does nothing
* finally, dlfb_release_urb_work is called, it increases the semaphore
count by 1, although it should increase it by 2
So, the semaphore count is decreasing over time, and this causes gradual
performance degradation.
Note that in the current kernel, the "up" function may be called from
interrupt and it may race with the "down" function called by another
thread, so we don't have to offload the call of "up" to a workqueue at
all. This patch removes the workqueue code. The patch also changes
"down_interruptible" to "down" in dlfb_free_urb_list, so that we will
clean up the driver properly even if a signal arrives.
With this patch, the performance of udlfb no longer degrades.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
[b.zolnierkie: fix immediatelly -> immediately typo]
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
* Return an error code without storing it in an intermediate variable.
* Delete the label "error" and local variable "retval"
which became unnecessary with this refactoring.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Cc: Bernie Thompson <bernie@plugable.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Driver generates lots of alignment trap exceptions on ARM.
Fix that by replacing typecasting of odd addresses with
byte shifting and remove uneccessary typecasting.
Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Cc: Bernie Thompson <bernie@plugable.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Use dev_err() and dev_info() instead of pr_err() and pr_info().
USB device is used as argument to dev_*() functions for probe
and urb manipulation, FB device for framebuffer related info.
Also noisy device probe output was partly removed as idVendor,
idProduct, name and serial are already printed by usb core,
and partly turned into debug output.
Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Cc: Bernie Thompson <bernie@plugable.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Both dlfb_fix and fb_device_attrs are never written to, so
it is safe to make them const.
Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Cc: Bernie Thompson <bernie@plugable.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Variable 'dev' is usually used for 'struct device'. Therefore
rename driver private data to dlfb to avoid confusion once
driver will be using dev_*() logging functions.
Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Cc: Bernie Thompson <bernie@plugable.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
These warnings comes from times of driver development and do
not carry any usefull debugging information.
Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Cc: Bernie Thompson <bernie@plugable.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
gdev is not really needed as the same content can be read
from udev->dev.
Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Cc: Bernie Thompson <bernie@plugable.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
'urb' is not needed and can be removed.
Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Cc: Bernie Thompson <bernie@plugable.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
The script "checkpatch.pl" pointed information out like the following.
WARNING: void function return statements are not generally useful
Thus remove such a statement in the affected functions.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Cc: Bernie Thompson <bernie@plugable.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Replace the specification of a data structure by a pointer dereference
as the parameter for the operator "sizeof" to make the corresponding size
determination a bit safer according to the Linux coding style convention.
This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Cc: Bernie Thompson <bernie@plugable.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
While usb_control_msg function expects timeout in miliseconds, a value
of HZ is used. Replace it with USB_CTRL_GET_TIMEOUT and also fix error
message which looks like:
udlfb: Read EDID byte 78 failed err ffffff92
as error is either negative errno or number of bytes transferred use %d
format specifier.
Returned EDID is in second byte, so return error when less than two bytes
are received.
Fixes: 18dffdf891 ("staging: udlfb: enhance EDID and mode handling support")
Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Cc: Bernie Thompson <bernie@plugable.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
If dlfb_usb_probe drops to error path then there is only one
kref_init() call and no kref_get(), so second kref_put() leads to
use after free.
The patch removes superfluous kref_put on dlfb_usb_probe error path.
Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Anton Vasilyev <vasilyev@ispras.ru>
Cc: Bernie Thompson <bernie@plugable.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
usb_device_id are not supposed to change at runtime. All functions
working with usb_device_id provided by <linux/usb.h> work with
const usb_device_id. So mark the non-const structs as const.
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Cc: Steve Glendinning <steve.glendinning@shawell.net>
Cc: Bernie Thompson <bernie@plugable.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Add const to bin_attribute structures as they are only passed to the
functions sysfs_{remove/create}_bin_file or
device_{remove/create}_bin_file. The corresponding arguments are of
type const, so declare the structures to be const.
Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Cc: Julia Lawall <Julia.Lawall@lip6.fr>
Cc: Bernie Thompson <bernie@plugable.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Drop log level for blanking from info to debug. Xorg likes to habitually
unblank when already unblanked and this can fill up logs over a long period
of time.
Signed-off-by: Mike Gerow <gerow@google.com>
Cc: bernie@plugable.com
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Add the missing endianness conversions when printing the USB
device-descriptor idVendor, idProduct and bcdDevice fields during probe.
Signed-off-by: Johan Hovold <johan@kernel.org>
Cc: Steve Glendinning <steve.glendinning@shawell.net>
Cc: Bernie Thompson <bernie@plugable.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Allocate buffers on HEAP instead of STACK for local array
that is to be sent using usb_control_msg().
Signed-off-by: Maksim Salau <maksim.salau@gmail.com>
Cc: Bernie Thompson <bernie@plugable.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Small minor cleanup.
This patch removes unneeded initializations of variables
in few places in different functions and one empty line.
Signed-off-by: Alexey Klimov <klimov.linux@gmail.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
The vfree() function performs also input parameter validation. Thus the test
around the call is not needed.
This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Instead of dereference each byte let's use %*ph specifier in the printk()
calls.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
The drivers/video directory is a mess. It contains generic video related
files, directories for backlight, console, linux logo, lots of fbdev
device drivers, fbdev framework files.
Make some order into the chaos by creating drivers/video/fbdev
directory, and move all fbdev related files there.
No functionality is changed, although I guess it is possible that some
subtle Makefile build order related issue could be created by this
patch.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Rob Clark <robdclark@gmail.com>
Acked-by: Jingoo Han <jg1.han@samsung.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
