With the integration of the mac80211 multiqueue patches it has become possible that the
mac80211 layer modifies the number of TX queues that is stored inside the ieee80211_hw
structure, especially when multi-queue is not selected.
The rt2x00 drivers are not well suited to handle that situation, as they allocate the
queue structures before mac80211 has modified the number of queues it is going to use,
and also expect the number of allocated queues to match the hardware implementation.
Hence, ensure that rt2x00 maintains by itself the number of queues that the hardware
supports, and, at the same time, making is not dependent on the preservation of contents
inside a mac80211 structure.
Signed-off-by: Gertjan van Wingerde <gwingerde@kpnplanet.nl>
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Move the last remaining information details read from ieee80211_tx_control
in the drivers to the txentry_desc structure. After this we can
remove ieee80211_tx_control from the argument list for the callback function,
which makes it easier when the control information is moved into skb->cb
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The tx_status enumeration was broken since the introduction
of rt61pci. That driver uses different values to report the
status of the tx action.
This would lead to frames that were reported as success but
actually failed to be send out, or frames that were neither
successfull or failure which were reported as failure.
Fix this by change the TX status reporting and more explicitely
check for failure or success. Note that a third possibility is
added "unknown". Not all hardware (USB) can report the actual
TX status, for rt61pci some frames will receive this status
because the TXdone handler is never called for those frames.
This unknown will now be handled as neither success or failure,
so we no longer increment the failure counter while this conclusion
could not be determined from the real status of the frame.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
trying to clean up the signal/noise code. the previous code in mac80211 had
confusing names for the related variables, did not have much definition of
what units of signal and noise were provided and used implicit mechanisms from
the wireless extensions.
this patch introduces hardware capability flags to let the hardware specify
clearly if it can provide signal and noise level values and which units it can
provide. this also anticipates possible new units like RCPI in the future.
for signal:
IEEE80211_HW_SIGNAL_UNSPEC - unspecified, unknown, hw specific
IEEE80211_HW_SIGNAL_DB - dB difference to unspecified reference point
IEEE80211_HW_SIGNAL_DBM - dBm, difference to 1mW
for noise we currently only have dBm:
IEEE80211_HW_NOISE_DBM - dBm, difference to 1mW
if IEEE80211_HW_SIGNAL_UNSPEC or IEEE80211_HW_SIGNAL_DB is used the driver has
to provide the maximum value (max_signal) it reports in order for applications
to make sense of the signal values.
i tried my best to find out for each driver what it can provide and update it
but i'm not sure (?) for some of them and used the more conservative guess in
doubt. this can be fixed easily after this patch has been merged by changing
the hardware flags of the driver.
DRIVER SIGNAL MAX NOISE QUAL
-----------------------------------------------------------------
adm8211 unspec(?) 100 n/a missing
at76_usb unspec(?) (?) unused missing
ath5k dBm dBm percent rssi
b43legacy dBm dBm percent jssi(?)
b43 dBm dBm percent jssi(?)
iwl-3945 dBm dBm percent snr+more
iwl-4965 dBm dBm percent snr+more
p54 unspec 127 n/a missing
rt2x00 dBm n/a percent rssi+tx/rx frame success
rt2400 dBm n/a
rt2500pci dBm n/a
rt2500usb dBm n/a
rt61pci dBm n/a
rt73usb dBm n/a
rtl8180 unspec(?) 65 n/a (?)
rtl8187 unspec(?) 65 (?) noise(?)
zd1211 dB(?) 100 n/a percent
drivers/net/wireless/ath5k/base.c: Changes-licensed-under: 3-Clause-BSD
Signed-off-by: Bruno Randolf <br1@einfach.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This
* makes the queue number passed to drivers a u16
(as it will be with skb_get_queue_mapping)
* removes the useless queue number defines
* splits hw->queues into hw->queues/ampdu_queues
* removes the debugfs files for per-queue counters
* removes some dead QoS code
* removes the beacon queue configuration for IBSS
so that the drivers now never get a queue number
bigger than (hw->queues + hw->ampdu_queues - 1)
for tx and only in the range 0..hw->queues-1 for
conf_tx.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Use the rt2x00 queue enumeration as much as possible,
removing the usage of the mac80211 queue numbering
wherever it is possible.
This makes it easier for mac80211 to change it queue
identification scheme without having to deal with
big changes in the rt2x00 code.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
There was an obvious typo in LED structure
initialization which caused the radio and quality/activity
leds to be incorrectly initialized which resulted in
the leds not being enabled.
Additionally add the rt2x00led_led_activity() handler
that will enable TX/RX activity leds when the radio
is being enabled.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The timing settings for 1MBs should exclude
the short preamble bit since that only applies
to 2MBs, 5.5MBs and 11MBs.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Implement triggers inside rt2x00 itself based
on input from mac80211. This replaces the method
of using the mac80211 trigger events which do
not work for USB drivers due to the scheduling
requirement.
After this patch RT2500USB_LEDS and RT73USB_LEDS
no longer need to be tagged as broken since they
now support LED handling again without having to
check for in_atomic().
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The TO_DS filter does not only depend on the FIF_PROMISC_IN_BSS flag
provided by mac80211, but also on the intf_ap_count count.
This makes sense, since when Master mode is active, we should all frames
that are send to the active AP (the device itself).
This means that when an interface is added we should force the
packet filter to be updated during the next mac80211 call of
configure_filter() to make sure the intf_ap_count field is checked.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
rt73usb and rt2500usb used in_atomic to determine
if a configuration step should be rescheduled or not.
Since in_atomic() is not a valid method to determine
if sleeping is allowed we should fix the way this is handled
by adding a new flag to rt2x00.
In addition mark LED class support for the drivers broken
since that also uses the broken in_atomic() method but
so far no solution exists to have LED triggers work only
in scheduled context.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The rxdone_entry_desc structure contains 3 fields
which are always 1 or 0. We can safe 8 bytes by
replacing them with a single dev_flags fields which
contain the flags for those settings.
Additionally we can remove the OFDM flag since it
is no longer used since the introduction of the
SIGNAL_PLCP flag.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Only rt2400pci can have the preamble bit set in the PLCP value,
for all other drivers it should not be cleared since that will
conflict with the plcp values for OFDM rates.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
After sampling hundreds of RX frame descriptors,
the results were conclusive:
- The Ralink documentation regarding the SIGNAL and RSSI are wrong.
It turns out that of the 5 BBR registers, we should not use BBR0 and BBR1
for SIGNAL and RSSI respectively, but actually BBR1 and BBR2.
BBR0 does show values, but the exact meaning remains unclear,
but they cannot be translated into a SIGNAL or RSSI field.
BBR3, BBR4 and BBR5 are always 0, so their meaning is unknown.
As it turns out, the reported SIGNAL is the PLCP value, this
in contradiction to what was expected looking at rt2500pci which
only reported the PLCP values for OFDM rates and bitrate values
for CCK rates.
This means we should let the driver raise the flag about the contents
of the SIGNAL field so rt2x00lib can always do the right thing based
on what the driver reports.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Due to a terrible typo the RX DMA base address
was initialized to the beacon base address.
Obviously bad things happen with bugs like that....
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Whatever mode we are in, according to the legacy drivers
we should always enable TSF ticking/counting.
We should also always enable the TBCN/TBTT field,
this field is only disabled during beacon regeneration.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Rename config_preamble() to config_erp() and cleanup argument
list by putting it all into a single structure.
This will make the function more meaningful and easier to
expand later. This second option is mostly intended to make
the patch "mac80211: proper short-slot handling" from Johannes Berg
easier to apply for rt2x00.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
rt2x00lib should filter SW diversity out before sending any configuration
changes to the driver. When rt2x00lib fails to do this, it is important
that such events are reported because it _must_ be fixed.
So upgrading the error level to a BUG_ON() which will make sure
this bug gets noticed whenever it happens.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
We should not write 0 to the beacon sync register during
config_intf() since that will clear out the beacon interval
and forces the beacon to be send out at the lowest interval.
(reported by Mattias Nissler).
The side effect of the same bug was that while working with
multiple virtual AP interfaces a change for any of those
interfaces would disable beaconing untill an beacon update
was provided.
This is resolved by only updating the TSF_SYNC value during
config_intf(). In update_beacon() we disable beaconing
temporarily to prevent fake beacons to be transmitted.
Finally kick_tx_queue() will enable beaconing again.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Don't wildly pass any number for num_rates to rt2x00lib,
instead pass which type of rates are supported (CCK, OFDM).
Same for num_modes but then for the 2GHZ and 5GHZ band.
This makes the interface look much nicer and makes
extending it later easier.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Specifications indicate the TSF registers are read-only,
so there is no point in writing 0 to those registers.
As far as I know there isn't another way to reset the
TSF registers. So removing these callbacks will notify
mac80211 about the lack of support.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
As Adam Baker reported the DMA address for the
descriptor base was incorrectly initialized in
the PCI drivers.
Instead of the DMA base for the descriptor, the
DMA base for the data was passed resulting in a
broken TX/RX state for PCI drivers.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This adds a new flag for the skb_frame_desc structure which is used to tag
rts/cts frames that are generated by the driver. Through the tag we can
recognize frames we have generated ourselves, so we don't report their tx
status to mac80211.
This patch is based on the original patch by
Mattias Nissler <mattias.nissler@gmx.de>.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Remove the debug messages regarding initialization from
EEPROM. The values are vendor specific, and are not really
needed for debug purposes. If they ever become usefull we
still have access to them through debugfs which also
prints the exact same values...
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Make use of the led triggers provided by mac80211 to control
the led status. This can be enabled through a per-driver
configuration option which will automatically enable the
generic handler in rt2x00lib.
This has been enabled for rt2500usb and rt73usb for the moment
since the led class will call set_brightness in irq context which
will not work correctly with the usb drivers who need to sleep.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
As Johannes Berg indicated the BEACON and AFTER_BEACON
queue indeces in mac80211 should be removed because they
are too hardware specific. This patch adds the queue index
defines into rt2x00queue.h and removes the dependency of
the defines inside mac80211.h.
Also move rt2x00pci_beacon_update() into rt2400pci and
rt2500pci individually since it is no longer a generic
function since rt61 and rt2800 no longer use that.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Rework the interface handling. Delete the interface structure
and replace it with a per-interface structure. This changes the
way rt2x00 handles the active interface drastically.
Copy ieee80211_bss_conf to the this rt2x00_intf structure during
the bss_info_changed() callback function. This will allow us to
reference it later, and removes the requirement for the device flag
SHORT_PREAMBLE flag which is interface specific.
Drivers receive the option to give the maximum number of virtual
interfaces the device can handle. Virtual interface support:
rt2400pci: 1 sta or 1 ap, * monitor interfaces
rt2500pci: 1 sta or 1 ap, * monitor interfaces
rt2500usb: 1 sta or 1 ap, * monitor interfaces
rt61pci: 1 sta or 4 ap, * monitor interfaces
rt73usb: 1 sta or 4 ap, * monitor interfaces
At the moment none of the drivers support AP and STA interfaces
simultaneously, this is a hardware limitation so future support
will be very unlikely.
Each interface structure receives its dedicated beacon entry,
with this we can easily work with beaconing while multiple master
mode interfaces are currently active.
The configuration handlers for the MAC, BSSID and type are
often called together since they all belong to the interface
configuration. Merge the 3 configuration calls and cleanup
the API between rt2x00lib and the drivers. While we are cleaning
up the interface configuration anyway, we might as well clean up
the configuration handler as well.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This introduces a big queue handling overhaul, this also
renames "ring" to "queues".
Move queue handling into rt2x00queue.c and the matching header,
use Kerneldoc to improve rt2x00 library documentation.
Access to the queues is now protected under a spinlock, this
to prevent race conditions which could corrupt the indexing
system of the queue.
Each queue entry allocates x bytes for driver/device specific data,
this cleans up the queue structure significantly and improves
code readability.
rt2500usb no longer needs 2 entries in the beacon queue to correctly
send out the guardian byte. This is now handled in the entry specific
structure.
rt61 and rt73 now use the correct descriptor size for beacon frames,
since this data is written into the registers not the entire TXD
descriptor was used but instead of a subset of it named TXINFO.
Finally this also fixes numerous other bugs related to incorrect
beacon handling or beacon related code.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This adds 2 new states which both are used to toggle
the RX. These new states are required for usage
inside the link tuner thread, because the normal
RX toggling will stop the link tuner thread.
While it is possible that the link tuner thread itself
is the caller of the RX toggle (when using software
antenna diversity).
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This patch (based on Ron Rindjunsky's) creates a framework for
a unified way to pass BSS configuration to drivers that require
the information, e.g. for implementing power save mode.
This patch introduces new ieee80211_bss_conf structure that is
passed to the driver via the new bss_info_changed() callback
when the BSS configuration changes.
This new BSS configuration infrastructure adds the following
new features:
* drivers are notified of their association AID
* drivers are notified of association status
and replaces the erp_ie_changed() callback. The patch also does
the relevant driver updates for the latter change.
Signed-off-by: Ron Rindjunsky <ron.rindjunsky@intel.com>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Prior to enabling the radio rt2x00lib should go through all
rings and for each entry should call the callback function
init_txentry() and init_rxentry().
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Use the MY_BSS descriptor field to determine if the
received frame belongs to the same BSS as the interface.
This can be used by rxdone to determine if the frame
should be updated or not.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Send the skb structure with write_tx_desc() and use
the skbdesc structure to read all information about
the frame. This saves several arguments in the function
definition and it is easier to send more information
later as well.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The packet filter flags don't belong in the interface structure
because they are device based instead of interface based.
So move the filter fields out of struct interface and into rt2x00_dev.
Additionally we shouldn't change the filter based on the working
mode, if such a thing is needed than mac80211 should have done that.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
These flags used to be fixed to one in rt2500pci_config_type, which
caused the beacon timer interrupt to fire. This would lead to
rt2x00lib_beacondone adding work which called
rt2x00lib_beacondone_scheduled which called ieee80211_beacon_get which
printed an error about not having any beacon data.
With this patch, these interrupts are only generated when the interface
is configured to send beacons.
Signed-off-by: Matthijs Kooijman <matthijs@stdin.nl>
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Extend word field definitions for the PLCP words
in the TX descriptor to contain the BBP fields as well.
This will remove rt2400pci_write_tx_desc() from the
checkstack script.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
DRV_NAME was always set to the KBUILD_MODNAME value,
lets clean everything up by removing DRV_NAME and just
use KBUILD_MODNAME directly.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
rt2400pci, rt2500pci and rt61 require different
txdone handling, but the code that pushes the frame
upstream and cleans up the entry is identical to
all of them.
This will create the function rt2x00pci_txdone()
to remove the duplicate code.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Add a flag to struct txdata_entry_desc that specifies whether an ack for the
frame is to be expected. Use this flag to set the ACK bit in the tx descriptor.
Previously, the ACK bit could be set incorrectly on CTS-to-self frames, so they
caused retries and were reported to be failed in the txdone handlers.
Signed-off-by: Mattias Nissler <mattias.nissler@gmx.de>
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Coverty indicated that data_desc with a single
element array is bad coding style. This removes
the structure and forces everybody to use __le32.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Some register accesses need rt2x00dev to be non-const
they all need modifying so the prototype is consistent.
Signed-off-by: Adam Baker <linux@baker-net.org.uk>
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cleanup if-statements for simple 1/0 register field values.
This also fixes a endian bug in rt2500usb when working
with the PHY_CSR2 initialization. As well as a bug
in the enabling of the LED in rt73usb.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Although ANTENNA_SW_DIVERSITY should never be send
to the driver, we should still handle it to prevent bugs.
But instead of defaulting to ANTENNA_HW_DIVERSITY we
should default to ANTENNA_B instead.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
mac80211 has 3 values for the antenna setup:
0 - default
1 - use antenna 1
2 - use antenna 2
This means that rt2x00 should store the default value
from the EEPROM somwhere and use that when mac80211 indicates
that the antenna setup is 0.
This also implies that rt2x00 should no longer write the
hw->config.antenna_sel_* values based on the EEPROM input.
This also adds the basis in rt2x00lib for correct software
diversity handling. By default rt2x00lib will now configure
antenna B instead of hardware diversity.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Move all link quality statistics variables into
the link_qual structure. This cleans up the link
structure and allows us to use it for more then
just statistics.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Reorganize configuration handling by creating a extra
structure which contains precalculated values based
on the mac80211 values which are usefull for all
individual drivers.
This also fixes the preamble configuration problem,
up untill now preamble was never configured since
by default the rate->val value was used when changing
the mode.
Now rate->val will only be used to set the basic rate mask.
The preamble configuration will now be done correctly
through the erp_ie_changed callback function.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
get_duration expects all speeds to be passed in 100kbs,
this means that passing 2 is incorrect and should be raised to 20
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
All drivers use the same values for TSF sync,
this will move the value determination into rt2x00config.c,
and the definition for the values to rt2x00reg.h
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
As reported by Modestas Vainius, enabling rkfill in 1 driver and
disabling it in a second could cause a NULL pointer exception when
the rfkill-disabled driver still sets the CONFIG_SUPPORT_HW_BUTTON flag.
Furthermore, rfkill expects the timeout as a value in milliseconds
instead of jiffies. Also increase the timeout to a second,
since this 250ms would be overkill.
Also the flag DEVICE_ENABLED_RADIO_HW is causing problems
for devices which do not support the hardware button
while rfkill is enabled in the driver.
To remidy this we should inverse the flag and its meaning,
rename the flag to DEVICE_DISABLED_RADIO_HW this means that
by default the radio is enabled by the hardware button (if present)
and can only be disabled explicitely.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
