* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6: (1699 commits)
bnx2/bnx2x: Unsupported Ethtool operations should return -EINVAL.
vlan: Calling vlan_hwaccel_do_receive() is always valid.
tproxy: use the interface primary IP address as a default value for --on-ip
tproxy: added IPv6 support to the socket match
cxgb3: function namespace cleanup
tproxy: added IPv6 support to the TPROXY target
tproxy: added IPv6 socket lookup function to nf_tproxy_core
be2net: Changes to use only priority codes allowed by f/w
tproxy: allow non-local binds of IPv6 sockets if IP_TRANSPARENT is enabled
tproxy: added tproxy sockopt interface in the IPV6 layer
tproxy: added udp6_lib_lookup function
tproxy: added const specifiers to udp lookup functions
tproxy: split off ipv6 defragmentation to a separate module
l2tp: small cleanup
nf_nat: restrict ICMP translation for embedded header
can: mcp251x: fix generation of error frames
can: mcp251x: fix endless loop in interrupt handler if CANINTF_MERRF is set
can-raw: add msg_flags to distinguish local traffic
9p: client code cleanup
rds: make local functions/variables static
...
Fix up conflicts in net/core/dev.c, drivers/net/pcmcia/smc91c92_cs.c and
drivers/net/wireless/ath/ath9k/debug.c as per David
All file_operations should get a .llseek operation so we can make
nonseekable_open the default for future file operations without a
.llseek pointer.
The three cases that we can automatically detect are no_llseek, seq_lseek
and default_llseek. For cases where we can we can automatically prove that
the file offset is always ignored, we use noop_llseek, which maintains
the current behavior of not returning an error from a seek.
New drivers should normally not use noop_llseek but instead use no_llseek
and call nonseekable_open at open time. Existing drivers can be converted
to do the same when the maintainer knows for certain that no user code
relies on calling seek on the device file.
The generated code is often incorrectly indented and right now contains
comments that clarify for each added line why a specific variant was
chosen. In the version that gets submitted upstream, the comments will
be gone and I will manually fix the indentation, because there does not
seem to be a way to do that using coccinelle.
Some amount of new code is currently sitting in linux-next that should get
the same modifications, which I will do at the end of the merge window.
Many thanks to Julia Lawall for helping me learn to write a semantic
patch that does all this.
===== begin semantic patch =====
// This adds an llseek= method to all file operations,
// as a preparation for making no_llseek the default.
//
// The rules are
// - use no_llseek explicitly if we do nonseekable_open
// - use seq_lseek for sequential files
// - use default_llseek if we know we access f_pos
// - use noop_llseek if we know we don't access f_pos,
// but we still want to allow users to call lseek
//
@ open1 exists @
identifier nested_open;
@@
nested_open(...)
{
<+...
nonseekable_open(...)
...+>
}
@ open exists@
identifier open_f;
identifier i, f;
identifier open1.nested_open;
@@
int open_f(struct inode *i, struct file *f)
{
<+...
(
nonseekable_open(...)
|
nested_open(...)
)
...+>
}
@ read disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
<+...
(
*off = E
|
*off += E
|
func(..., off, ...)
|
E = *off
)
...+>
}
@ read_no_fpos disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
... when != off
}
@ write @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
<+...
(
*off = E
|
*off += E
|
func(..., off, ...)
|
E = *off
)
...+>
}
@ write_no_fpos @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
... when != off
}
@ fops0 @
identifier fops;
@@
struct file_operations fops = {
...
};
@ has_llseek depends on fops0 @
identifier fops0.fops;
identifier llseek_f;
@@
struct file_operations fops = {
...
.llseek = llseek_f,
...
};
@ has_read depends on fops0 @
identifier fops0.fops;
identifier read_f;
@@
struct file_operations fops = {
...
.read = read_f,
...
};
@ has_write depends on fops0 @
identifier fops0.fops;
identifier write_f;
@@
struct file_operations fops = {
...
.write = write_f,
...
};
@ has_open depends on fops0 @
identifier fops0.fops;
identifier open_f;
@@
struct file_operations fops = {
...
.open = open_f,
...
};
// use no_llseek if we call nonseekable_open
////////////////////////////////////////////
@ nonseekable1 depends on !has_llseek && has_open @
identifier fops0.fops;
identifier nso ~= "nonseekable_open";
@@
struct file_operations fops = {
... .open = nso, ...
+.llseek = no_llseek, /* nonseekable */
};
@ nonseekable2 depends on !has_llseek @
identifier fops0.fops;
identifier open.open_f;
@@
struct file_operations fops = {
... .open = open_f, ...
+.llseek = no_llseek, /* open uses nonseekable */
};
// use seq_lseek for sequential files
/////////////////////////////////////
@ seq depends on !has_llseek @
identifier fops0.fops;
identifier sr ~= "seq_read";
@@
struct file_operations fops = {
... .read = sr, ...
+.llseek = seq_lseek, /* we have seq_read */
};
// use default_llseek if there is a readdir
///////////////////////////////////////////
@ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier readdir_e;
@@
// any other fop is used that changes pos
struct file_operations fops = {
... .readdir = readdir_e, ...
+.llseek = default_llseek, /* readdir is present */
};
// use default_llseek if at least one of read/write touches f_pos
/////////////////////////////////////////////////////////////////
@ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read.read_f;
@@
// read fops use offset
struct file_operations fops = {
... .read = read_f, ...
+.llseek = default_llseek, /* read accesses f_pos */
};
@ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write.write_f;
@@
// write fops use offset
struct file_operations fops = {
... .write = write_f, ...
+ .llseek = default_llseek, /* write accesses f_pos */
};
// Use noop_llseek if neither read nor write accesses f_pos
///////////////////////////////////////////////////////////
@ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
identifier write_no_fpos.write_f;
@@
// write fops use offset
struct file_operations fops = {
...
.write = write_f,
.read = read_f,
...
+.llseek = noop_llseek, /* read and write both use no f_pos */
};
@ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write_no_fpos.write_f;
@@
struct file_operations fops = {
... .write = write_f, ...
+.llseek = noop_llseek, /* write uses no f_pos */
};
@ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
@@
struct file_operations fops = {
... .read = read_f, ...
+.llseek = noop_llseek, /* read uses no f_pos */
};
@ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
@@
struct file_operations fops = {
...
+.llseek = noop_llseek, /* no read or write fn */
};
===== End semantic patch =====
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Julia Lawall <julia@diku.dk>
Cc: Christoph Hellwig <hch@infradead.org>
wl1271 driver is under heavy development but on the other hand the older
wl1251 driver is currently considered more as a legacy driver. To make it
easier to develop wl1271 features move wl1251 to it's own directory,
drivers/net/wireless/wl1251.
There are no functional changes, only moving of files. One regression
is that Kconfig won't be updated automatically and user needs to enable
wl1251 manually with an older config file.
Signed-off-by: Kalle Valo <kvalo@adurom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Add required suspend/resume support to prevent the SDIO
core from removing our card completely during system suspend.
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Tested-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Enable runtime PM for the wl1271 SDIO device.
We request power whenever the WLAN interface is brought up,
and release it after the WLAN interface is taken down.
As a result, power is released immediately after probe returns,
since at that point power has not been explicitly requested yet
(i.e. the WLAN interface is still down).
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Acked-by: Luciano Coelho <luciano.coelho@nokia.com>
Tested-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
In the NVS/INI-parameters for the driver/firmware there is the FEM
(front end module) selection option, which may configure the hardware FEM
via autodetection or manual selection. So far, there has been support for
manual selection only.
Add support for FEM autodetection.
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
One __attribute__ ((packed)) has been accidentally introduced in commit
be86cbea1e. This patch changes it to __packed.
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Currently a command to initialize extended radio parameter tables in the
hardware is missing.
Add the initialization
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
In the event of a hardware failure, reconfiguring a live connection back
with the wl1271 chip does not work as expected. The chip has management
features which require setting up the association from scratch to work
correctly. To ensure this is done every time, in managed mode, when associated,
indicate connection loss to the mac80211 before asking to reconfigure the
hardware.
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Tested-by: Tuomas Katila <ext-tuomas.2.katila@nokia.com>
Reviewed-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Due to legacy reason, dating back to when the wl1251 and wl1271 still were
a unified driver, some work-structures are initialized on hardware startup.
The hardware recovery code creates a scenario in which it is possible for a
workstruct to be re-initialized while the work-function itself is running,
which causes a kernel WARNing and a subsequent reboot.
To remedy this, move the work initialization calls to the hw allocation,
which is the logically correct place for them anyway.
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Tested-by: Tuomas Katila <ext-tuomas.2.katila@nokia.com>
Reviewed-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Instead of sending one packet at a time to the firmware, try to
send all available packets at once.
This optimization decreases the number of transactions, which saves
CPU cycles and increases network throughput.
Signed-off-by: Ido Yariv <ido@wizery.com>
Tested-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Instead of retrieving one packet at a time from the firmware, try to
retrieve all available packets at once.
This optimization decreases the number of transactions, which saves
CPU cycles and increases network throughput.
Signed-off-by: Ido Yariv <ido@wizery.com>
Tested-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
The HW supports up to 4095 bytes transfers via SPI. The SPI read & write
operations do not handle larger transfers, causing the HW to stall in such
cases.
Fix this by fragmenting large transfers into smaller chunks, and
transferring each one separately.
Signed-off-by: Ido Yariv <ido@wizery.com>
Tested-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Make this go away (happens when building with a separate object
directory):
Assembler messages:
Fatal error: can't create drivers/net/wireless/wl12xx/.tmp_wl12xx_platform_data.o: No such file or directory
drivers/net/wireless/wl12xx/wl12xx_platform_data.c: In function 'wl12xx_get_platform_data':
drivers/net/wireless/wl12xx/wl12xx_platform_data.c:28: error: cannot open drivers/net/wireless/wl12xx/.tmp_wl12xx_platform_data.gcno
drivers/net/wireless/wl12xx/wl12xx_platform_data.c:28: confused by earlier errors, bailing out
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
This patch improves connection reliability by choosing the lowest basic
rate for null-func frames (which increases their range, as the firmware does
not do rate fall-back for null-func frames.) Also, increase the PSM entry
retry-counter.
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Teemu Paasikivi <ext-teemu.3.paasikivi@nokia.com>
Tested-by: Tuomas Katila <ext-tuomas.2.katila@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Currently then dwell times for each channel in scans is set to an overly
long value, and excessive number of probe-requests are transmitted on each
channel (for active scans.)
Based on testing, comparable results can be received with smaller dwell-time,
and, with fever probe-requests - in fact, reducing the number of probe-requests
to 2 seems to increase the number of found results.
Configure more optimal values for per channel dwell times. Comparison for the
different scan configurations (in my current office environment):
dwell-time 60000 3x probe-req == ~60 results
40000 3x probe-req == ~50 results
30000 3x probe-req == ~40 results
dwell-time 60000 2x probe-req == ~70 results
40000 2x probe-req == ~60 results
30000 2x probe-req == ~58 results
The above are results for a cumulative 3 scan run. For individual scans, the
number of results drop slightly more.
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Teemu Paasikivi <ext-teemu.3.paasikivi@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Currently, the driver does not handle a failing hardware command to scan in
any way - effectively, the scan machine will jam until the driver is shut down,
and future scan requests will just return -EBUSY to user space, resulting in
a type of busy-loop. The same problem occurs if the firmware fails to deliver
the scan completion event - add timeout for this.
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Teemu Paasikivi <ext-teemu.3.paasikivi@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
There is some probability of hardware failures, which currently go largely
undetected. Attempt to recover from these failures by shutting down the
hardware, and requesting mac80211 to reconfigure it.
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Teemu Paasikivi <ext-teemu.3.paasikivi@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Do this so the interface removal can be triggered from an upcoming hardware
failure recovery mechanism.
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Teemu Paasikivi <ext-teemu.3.paasikivi@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
The work cancelling has had several hazards, ranging from potentially
executing work after the driver is in OFF state, to executing work after
the driver and relevant memory structures are already removed.
Fix these.
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Teemu Paasikivi <ext-teemu.3.paasikivi@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
The current scan implementation can jam, if the scan request ends up
containing no work. This can especially happen if there is a scan request
with only 11a band channels for HW that does not support 11a.
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Incorrect TID was configured for TX frames. This resulted in incorrect
queues to be used for classes in transmission.
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
This patch always enables 11a band towards the mac80211, but prevents scanning
(and hence the usage of) 11a band channels if the chipset does not support it.
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
This patch reduces the rate of the null-func used to enter PSM on the last
retry as precaution.
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Instead of hardcoding 11a support, enable/disable driver support based on
the dual-mode-select parameter in the nvs-file general paramters.
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
The function is not used anywhere.
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
The current order causes driver releasing to fail in various ways, and causes
possible instability.
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
This removes a fixme. Also, it removes a redundant setting of the wake-up
conditions when exiting power save mode, which should improve performance.
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
The mac80211 inserts channels into a scan request in the same order the driver
registers them. Use this fact to optimize scan by ordering the channels so
that adjacent channels don't get scanned consecutively.
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
When we get no SSIDs in the scan request, we should force a passive scan in
all channels. This patch adds code to force the passive scan flag to be set
in that case.
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Reviewed-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
This code was a leftover of the previous scanning mechanism. The if is
totally unnecessary, since both branches do the same thing.
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Reviewed-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
In the scan state machine, the wl1271_mutex is unlocked first then relocked,
and then the scan state variables are modified.
This makes it possible for ieee80211_scan_complete to be called twice in some
scenarios, as the scan completion event from the firmware may be processed
while the mutex is unlocked.
To fix the issue, move the ieee80211_scan_complete call last in the function.
This is generally safer, but there still may be issues is functions calling
the scan state machine rely on states checked before the unlocking of the
global mutex.
(forward ported from 2.6.32 -- this is not strictly needed anymore, because
the mutex doesn't need to be unlocked anymore, but I'm applying this change
anyway, so that the call to ieee80211_scan_complete is in the same place)
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Saravanan Dhanabal <ext-saravanan.dhanabal@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Add a trigger to net_device changes to monitor for oper_state changes in order
to be able to inform the firmware when association is fully complete (including
the EAP negotiation.)
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Teemu Paasikivi <ext-teemu.3.paasikivi@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Implement the command function to send CMD_SET_STA_STATE to the firmware. This
is used to indicate that association (and the related EAP negotiation) are
complete.
This is used to tune WLAN-BT coexistense priority towards BT, improving BT
A2DP and SCO performance.
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Teemu Paasikivi <ext-teemu.3.paasikivi@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
As of Rev. 6.1.0.0.335, the ACX_SET_SMART_REFLEX_DEBUG command is
deprecated. This patch removes it from the wl1271 driver (it wasn't used
anyway).
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Reviewed-by: Saravanan Dhanabal <ext-saravanan.dhanabal@nokia.com>
Due to miscalculation of nvs_len, excessive data was sent to the
firmware.
Fix this by first setting nvs_ptr to point to the first NVS table,
and computing the total size of all NVS tables accordingly.
Signed-off-by: Ido Yariv <ido@wizery.com>
Tested-By: Tuomas Katila <ext-tuomas.2.katila@nokia.com>
Acked-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
typo - while looking for specific bits we should do a bitwise-AND instead of logical-AND.
Signed-off-by: Eliad Peller <eliad@wizery.com>
Acked-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
copy the rx_status directly to skb->cb (control buffer) instead of copying
it to a local struct and then copying it again (for each rx packet)
Signed-off-by: Eliad Peller <eliad@wizery.com>
Acked-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The wl1271 device is using a reference clock that may change
between board to board.
Make the ref_clock parameter configurable by board settings
instead of having a hard coded value in the sources.
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Remove the hard coded irq information, and instead take
the irq information from the board's platform data.
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Add a simple mechanism to pass platform data to the
SDIO instances of wl12xx.
This way there is no confusion over who owns the 'embedded data',
typechecking is preserved, and no possibility for the wrong driver to
pick up the data.
Originally proposed by Russell King.
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>