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: NMikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: NBartlomiej 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: NMikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
[b.zolnierkie: fix immediatelly -> immediately typo]
Signed-off-by: NBartlomiej 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: NLadislav Michl <ladis@linux-mips.org>
Cc: Bernie Thompson <bernie@plugable.com>
Signed-off-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

gdev is not really needed as the same content can be read
from udev->dev.
Signed-off-by: NLadislav Michl <ladis@linux-mips.org>
Cc: Bernie Thompson <bernie@plugable.com>
Signed-off-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: NKate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: NPhilippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Few parts of kernel define their own macro for aligning down so provide
a common define for this, with the same usage and assumptions as existing
ALIGN.

Convert also three existing implementations to this one.
Signed-off-by: NKrzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

Fix race conditions with unplug/replug behavior, in particular
take care not to hold up USB probe/disconnect for long-running
framebuffer operations and rely on usb to handle teardown.

Fix for kernel panic reported with new F17 multiseat support.
Reported-by: NKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NBernie Thompson <bernie@plugable.com>

Fixes earlier problems where monitor would not return from blank

Test with any DisplayLink-based USB 2.0 graphics adapter
sudo nano /sys/class/graphics/fb?/blank
and write out single digit FB_BLANK_* code from include/linux/fb.h

Supports on (0), blank (1), suspend (2,3), powerdown (4)
Signed-off-by: NBernie Thompson <bernie@plugable.com>
Signed-off-by: NFlorian Tobias Schandinat <FlorianSchandinat@gmx.de>

This kills off all of the dl_xxx() printk wrappers and simply stubs in a
pr_fmt() definition to accomplish the same thing.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

The edid length is fixed, so use the standard definition consistently.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

udlfb has undergone a fair bit of cleanup recently and is effectively at
the point where it can be liberated from staging purgatory and promoted
to a real driver.

The outstanding cleanups are all minor, with some of them dependent on
drivers/video headers, so these will be done incrementally from udlfb's
new home.
Requested-by: NBernie Thompson <bernie@plugable.com>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

Fix fb_defio bug in udlfb for multiple framebuffers

Previously when using fb_defio with multiple DisplayLink attached displays
udlfb incorrectly used a shared datastructure where it needed to have
one per fb_info struct. This was completely broken and caused all kinds of
problems, including rendering to one framebuffer affecting others.
Signed-off-by: NBernie Thompson <bernie@plugable.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Add module options for console and fb_defio

Convert fb_defio on/off switch to module option and add console option.

>From the command line, pass options to modprobe
modprobe udlfb defio=1 console=1

Or for permanent option, create file like /etc/modprobe.d/options with text
options udlfb defio=1 console=1

Accepted options:

fb_defio	Make use of the fb_defio (CONFIG_FB_DEFERRED_IO) kernel
		module to track changed areas of the framebuffer by page faults.
        	Standard fbdev applications that use mmap but that do not
		report damage, may be able to work with this enabled.
		Disabled by default because of overhead and other issues.

console		Allow fbcon to attach to udlfb provided framebuffers. This
		is disabled by default because fbcon will aggressively consume
		the first framebuffer it finds, which isn't usually what the
		user wants in the case of USB displays.
Signed-off-by: NBernie Thompson <bernie@plugable.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Enhance EDID and mode table handling

* Adds support for lower-end DL chips on higher-end monitors
* Adds support for using fbdev standard EDID parsing and handling
* Adds support for more dynamic reallocation of framebuffer, based on new EDID

Queries EDID from hardware with several retries then
queries DisplayLink chip for max pixel area via vendor descriptor.
Uses existing fbdev mode handling service funcations to build mode list
of common modes between adapter and monitor.
This enables lower-end chips (e.g. DL-125) to successfully pick a compatible
mode on higher end monitors (e.g. whose default mode is over 1280x1024).
Reallocate framebuffer if necessary in response to new max mode.
Signed-off-by: NBernie Thompson <bernie@plugable.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Revamp reference handling and synchronization for unload/shutdown

Udlfb is a "virtual" framebuffer device that really exists on
two separate stacks: at the bottom of the framebuffer interface,
and on top of USB.  During unload, there's no guarantee which
one will tear down first. So reference counting must be solid
to handle all possibilities and not access anything once its gone.
Signed-off-by: NBernie Thompson <bernie@plugable.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Remove metrics_misc sysfs attribute

Previously returned multiple values, which goes against sysfs guidelines.
Had been used for debugging to figure out which of the multiple
fbdev interfaces an app was using, but log file messages are sufficient.
Signed-off-by: NBernie Thompson <bernie@plugable.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Rework rendering for improved performance

Approx 10-20% gain avg across several "benchmarks": x11perf, gtkperf, glxgears
Moves from a single pre-alloc'd urb protected by a long-held mutex
To a list of (4) pre-alloc'd urbs which can be dispatched asynchonously

Improved rendering algorithm to hardware with lower CPU consumption,
fewer system memory accesses, and slightly higher compression.

Better scalability to multiple processors, especially with
multiple framebuffers active.
Signed-off-by: NBernie Thompson <bernie@plugable.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Rework probe to use refcounts and std functions

Because the different parts of the driver (usb, fbdev) tear down
in different orders, the driver previously could crash accessing
data that had already been freed.  Refcounting system used to handle.

Reworked probe to make use of refcounts, set mode using std fbops,
and set up sysfs and pre-allocated urbs.
Signed-off-by: NBernie Thompson <bernie@plugable.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Add sysfs controls for edid and performance metrics

There are 8 new files exposed in /sys/class/graphics/fb*

edid - returns 128 byte edid blog, suitable for parsing with parse-edid
metrics_bytes_identical
metrics_bytes_rendered
metrics_bytes_sent
metrics_cpu_kcycles_used
metrics_misc
and metrics_reset, which resets all perf metrics to zero

The 6 perf metrics are of type atomic_t.
So these metrics return precise results for short benchmarks, but
any test approx a minute or longer runtime may roll over.
Signed-off-by: NBernie Thompson <bernie@plugable.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Add functions to pre-allocate and free usb bulk urbs for core render path.

Udlfb currently allocates a single urb, guarded by a mutex, that is a key
bottleneck. Because udlfb sends so much data, preallocation is most efficient.

Functions will be used by new rendering functions in later patches.
Signed-off-by: NBernie Thompson <bernie@plugable.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Reorganize the location of a few things to be closer to related code
Signed-off-by: NBernie Thompson <bernie@plugable.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Eliminate checkpatch.pl warnings and errors so later patches in series are clean
Signed-off-by: NBernie Thompson <bernie@plugable.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Add dynamic modeset support

udlfb uses EDID to find the monitor’s preferred mode
udlfb no longer has fixed mode tables – it’s able to set any mode 
dynamically, from the standard VESA timing characteristics of the monitor.

Draws from probe and setmode code of both displaylink-mod 0.3 branch of 
Roberto De Ioris, and Jaya Kumar's displaylinkfb.
Lays foundation for defio support and making backbuffer optional.
With additional changes to minimize diffs and clean for checkpatch.pl style.

Does not yet include new ioctls or refcount/mutex code from displaylink-mod.

Tested to work with existing xf-video-displaylink X server unmodified.
Signed-off-by: NBernie Thompson <bernie@plugable.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

 

Fix printk format warning: use %td for ptrdiff:

drivers/staging/udlfb/udlfb.h:209: warning: format '%d' expects type 'int', but argument 3 has type 'long int'
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This updates the udlfb to the 0.2.3 version.

From: Roberto De Ioris <roberto@unbit.it>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

There are others remaining due to the __iomem namespace of the
framebuffer data pointer.

Cc: Roberto De Ioris <roberto@unbit.it>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This cleans up a bunch of checkpatch.pl warnings in the udlfb.h file.

Cc: Roberto De Ioris <roberto@unbit.it>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This adds the udlfb driver, a framebuffer driver for DisplayLink devices.


From: Roberto De Ioris <roberto@unbit.it>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>