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>

The Kconfig description for CONFIG_SBE_PMCC4_NCOMM says:

  If you have purchased this optional support you must say Y or M
  here to allow the driver to operate with the NCOMM product.

This is not correct as it can not be built as module,
this patch updates the description accordingly.
Signed-off-by: NMichael Prokop <mika@grml.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

In each case, the function has an unsigned return type, but returns a
negative constant to indicate an error condition.  For move_block_from_dma,
there is only one call and the return value is dropped, so it need not be
unsigned.  For labpc_eeprom_write, there is only one call and the result is
stored in a signed variable, so again the unsigned return type is not
necessary.

A sematic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@exists@
identifier f;
constant C;
@@

 unsigned f(...)
 { <+...
*  return -C;
 ...+> }
// </smpl>
Signed-off-by: NJulia Lawall <julia@diku.dk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

kmalloc() may fail, check for it.
Allocated memory is not freed.
Use IS_ERR() instead of strict checking.
Signed-off-by: NVasiliy Kulikov <segooon@gmail.com>
Cc: David Cross <david.cross@cypress.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Function get_user may fail. Check for it.
Signed-off-by: NVasiliy Kulikov <segooon@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Function put_user may fail. Check for it.
Signed-off-by: NVasiliy Kulikov <segooon@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Function get_user may fail. Check for it.
Signed-off-by: NVasiliy Kulikov <segooon@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Functions alloc_ieee80211 and register_netdev may fail. Check for it.
Signed-off-by: NVasiliy Kulikov <segooon@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Function kzalloc may fail. Check for it.
Signed-off-by: NVasiliy Kulikov <segooon@gmail.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>

Support writing default/backup edid via /sys/class/graphics/fb?/edid

Writing a backup edid blob to the 'edid' file will cause udlfb to
attempt to re-read the edid from hardware.
If we still don't have a good edid, it will use the backup edid instead.
The intent is to 1) enable user-supplied edid
2) enable udev rules to backup the last known good edid
for a device, and then provide that edid as a backup for all future starts
Signed-off-by: NBernie Thompson <bernie@plugable.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Fix big endian rendering bug (affects PowerPC)

Thanks to Christian Melki at Ericsson for finding and suggesting patch.
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>

Add ability to power off monitor with standard blanking interface

Used by X servers and others to manage power of dislpay
Signed-off-by: NBernie Thompson <bernie@plugable.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Restore fbdev character read and write support

Enables access to the framebuffer from simple reads and writes
to /dev/fb0 (or fb1, ...). Low performance, because of extra copy
and because udlfb must scan every pixel for changes. But very
useful for testing and simple image display, etc.
Signed-off-by: NBernie Thompson <bernie@plugable.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Add documentation for the udlfb framebuffer driver for DisplayLink devices.
Signed-off-by: NBernie Thompson <bernie@plugable.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Signed-off-by: NJavier Martinez Canillas <martinez.javier@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

We must reduce our own mtu when we reduce the mtu of any device we use
to transfer our packets. Otherwise we may accept to large packets which
gets dropped by the actual device.
Reported-by: NVasiliy Kulikov <segooon@gmail.com>
Signed-off-by: NSven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Information about dropped packets are usually only interesting for
debugging purposes and otherwise open the possibility to flood the logs
of the target machine with useless information.

pr_debug will not output those information on a nodebug kernel.
Reported-by: NVasiliy Kulikov <segooon@gmail.com>
Signed-off-by: NSven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

batman_if has the name of the net_dev as extra string in its own
structure, but also holds a reference to the actual net_device structure
which always has the current name of the device. This makes it
unneccessary and also more complex because we must update the name in
situations when we receive a NETDEV_CHANGENAME event.
Signed-off-by: NSven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch removes all remaining global variables and includes the
necessary bits into the bat_priv structure. It is the last
remaining piece to allow multiple concurrent mesh clouds on the
same device.
A few global variables have been rendered obsolete during the process
and have been removed entirely.
Signed-off-by: NMarek Lindner <lindner_marek@yahoo.de>
[sven.eckelmann@gmx.de: Rework on top of current version]
Signed-off-by: NSven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch replaces the static bat0 interface with a dynamic/abstracted
approach. It is now possible to create multiple batX interfaces by
assigning hard interfaces to them. Each batX interface acts as an
independent mesh network. A soft interface is removed once no hard
interface references it any longer.
Signed-off-by: NMarek Lindner <lindner_marek@yahoo.de>
[sven.eckelmann@gmx.de: Rework on top of current version]
Signed-off-by: NSven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

We must ensure that all interesting data is linear and not paged out to
access all information in a header or a full batman-adv related packet.
Otherwise we may drop packets which have non-linear headers but which
hold valid data.

This doesn't affect non-linear skbs which have all headers in a linear
head unless we must process the whole packet like in ogms or vis
packets.
Signed-off-by: NSven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

We can use skb_cow instead of a handwritten function to test and create
a writable skb buffer. This also allows us to pre-allocate headroom to
be able to send the data without re-allocating the buffer again to add
the ethernet header.
Signed-off-by: NSven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The vis information structure is used in a way that it can be transfered
directly as packet. It still had to be copied into a skb because of an
extra buffer used for the actual preparation of the data. This is
unnecessary and can be replaced by a simple clone instead of an full
copy before each send.

This makes also the send_raw_packet function obsolete.
Reported-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NSven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

All originator messages are send through aggregation buffers. Those
buffers can directly be allocated as skb to reduce the cost of
allocation an extra buffer and copying them to a new allocated skb
directly before it gets send.

Now only the skb must be cloned in case of send_packet_to_if as it gets
called by send_packet for each interface. Non-primary ogms must not
cloned at all because they will only send once and the forward_packet
structure is freed by send_outstanding_bat_packet afterwards.
Reported-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NSven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

batman-adv tries to resend broadcasts on all interfaces up to three
times. For each round and each interface it must provide a skb which
gets consumed by the sending function.

It is unnecessary to copy the data of each broadcast because the actual
data is either not shared or already copied by add_bcast_packet_to_list.
So it is enough to just copy the skb control data
Reported-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NSven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

my_skb_push provided an easy way to allocate enough headroom in
situation were we don't have enough space left and move the data pointer
to the new position, but we didn't checked wether we are allowed to
write to the new pushed header. This is for example a problem when the
skb was cloned and thus doesn't have a private data part.

my_skb_head_push now replaces my_skb_push by using skb_cow_head to
provide only a large enough, writable header without testing for the
rest of the (maybe shared) data. It will also move the data pointer
using skb_push when skb_cow_head doesn't fail.

This should give us enough flexibility in situation were skbs will be
queued by underlying layers and still doesn't unnecessarily copy the
data in situations when the skb was consumed right away during
dev_queue_xmit.
Reported-by: NMarek Lindner <lindner_marek@yahoo.de>
Signed-off-by: NSven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Batman-adv globally registered the batman-adv packet type and installed
a hook to batman_skb_recv(). Each interface receiving a packet with that
type would end up in this function which then had to loop through all
batman-adv internal interface structures to find the its meta data. The
more interfaces a system had the longer the loops might take. Each and
every packet goes through this function making it a performance critical
loop.

This patch installs the hook for each activated interface. The called
batman_skb_recv() can distinguish these calls, therefore avoiding the
loop through the interface structures.
Signed-off-by: NMarek Lindner <lindner_marek@yahoo.de>
[sven.eckelmann@gmx.de: Rework on top of current version]
Signed-off-by: NSven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

It is unnecessary to generate an icmp packet in an extra memory region
and than copying it to a new allocated skb.

This also resolved the problem that we do inform the user that we
couldn't send the packet because we couldn't allocate the socket buffer.
Signed-off-by: NSven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch implements a simple layer2 fragmentation to allow traffic
exchange over network interfaces with a MTU smaller than 1500 bytes. The
fragmentation splits the big packets into two parts and marks the frames
accordingly. The receiving end buffers the packets to reassemble the
orignal packet before passing it to the higher layers. This feature
makes it necessary to modify the batman-adv encapsulation for unicast
packets by adding a sequence number, flags and the originator address.
This modifcation is part of a seperate packet type for fragemented
packets to keep the original overhead as low as possible. This patch
enables the feature by default to ensure the data traffic can travel
through the network. But it also prints a warning to notify the user
about the performance implications.

Note: Fragmentation should be avoided at all costs since it has a
dramatic impact on the performance, especially when it comes wifi
networks. Instead of a single packet, 2 packets have to be sent! Not
only valuable airtime is wasted but also packetloss decreases the
throughput. A link with 50% packetloss and fragmentation enabled is
pretty much unusable.
Signed-off-by: NAndreas Langer <an.langer@gmx.de>
[sven.eckelmann@gmx.de: Rework on top of current version]
Signed-off-by: NSven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Signed-off-by: NMarek Lindner <lindner_marek@yahoo.de>
[sven.eckelmann@gmx.de: Rework on top of current version]
Signed-off-by: NSven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

to support multiple mesh devices later, we need to move global variables
like the queues into corresponding private structs bat_priv of the soft
devices.

Note that this patch still has a lot of FIXMEs and depends on the global
soft_device variable. This should be resolved later, e.g. by referencing
the parent soft device in batman_if.
Signed-off-by: NSimon Wunderlich <siwu@hrz.tu-chemnitz.de>
[sven.eckelmann@gmx.de: Rework on top of current version]
Signed-off-by: NSven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The Kernighan algorithm is not able to calculate the number of set bits
in parallel and the compiler cannot replace it with optimized
instructions.

The kernel provides specialised functions for each cpu which can either
use a software implementation or hardware instruction depending on the
target cpu.
Reported-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NSven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The Ethernet header is counted when transmitting a packet, so it should also
be counted when receiving a packet. With this patch, the rx_bytes and tx_bytes
statistics behave like an ordinary Ethernet interface.
Signed-off-by: NSimon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: NSven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Version 2010.1.0 of the extra kernel module was released and thus the
documentation should be updated and everything prepared for the the
upcoming patchset.
Signed-off-by: NSven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The changelog is only generated on standalone releases. Thus it has no
real value for the in-kernel version of batman-adv.
Reported-by: NAbraham Arce <abraham.arce.moreno@gmail.com>
Signed-off-by: NSven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>