linux-toradex.git/drivers/input/evdev.c, branch v3.3.5

Input: evdev - fix variable initialisation

2012-02-24T08:52:43+00:00

Commit 509f87c5f564 (evdev - do not block waiting for an event if fd
is nonblock) created a code path were it was possible to use retval
uninitialized.

This could lead to the xorg evdev input driver getting corrupt data
and refusing to work with log messages like
	AUO-Pixcir touchscreen: Read error: Success
	sg060_keys: Read error: Success
	AUO-Pixcir touchscreen: Read error: Success
	sg060_keys: Read error: Success
(for drivers auo-pixcir-ts and gpio-keys).

Signed-off-by: Heiko Stuebner 
Acked-by: Dima Zavin 
Signed-off-by: Dmitry Torokhov

Input: evdev - fix variable initialisation

2012-02-01T17:12:54+00:00

Commit 509f87c5f564 (evdev - do not block waiting for an event if fd
is nonblock) created a code path were it was possible to use retval
uninitialized.

This could lead to the xorg evdev input driver getting corrupt data
and refusing to work with log messages like
	AUO-Pixcir touchscreen: Read error: Success
	sg060_keys: Read error: Success
	AUO-Pixcir touchscreen: Read error: Success
	sg060_keys: Read error: Success
(for drivers auo-pixcir-ts and gpio-keys).

Signed-off-by: Heiko Stuebner 
Acked-by: Dima Zavin 
Signed-off-by: Dmitry Torokhov

Input: evdev - do not block waiting for an event if fd is nonblock

2011-12-30T23:26:35+00:00

If there is a full packet in the buffer, and we overflow that buffer
right after checking for that condition, it would have been possible
for us to block indefinitely (rather, until the next full packet) even if
the file was marked as O_NONBLOCK.

Cc: Jeff Brown 
Signed-off-by: Dima Zavin 
Signed-off-by: Dmitry Torokhov

Input: evdev - if no events and non-block, return EAGAIN not 0

2011-12-30T23:26:35+00:00

Signed-off-by: Dima Zavin 
Signed-off-by: Dmitry Torokhov

Input: evdev - only allow reading events if a full packet is present

2011-12-30T23:26:34+00:00

Without this, it was possible for the reader to get ahead of packet_head.
If the input device generated a partial packet *right* after the reader
got ahead, then we can get into a situation where the device is marked
readable, but read always returns 0 until the next packet is finished
(i.e a SYN is generated by the input driver).

This situation can also happen if we overflow the buffer while a reader
is trying to read an event out.

Signed-off-by: Dima Zavin 
Signed-off-by: Dmitry Torokhov

Input: evdev - try to wake up readers only if we have full packet

2011-06-18T09:54:02+00:00

We should only wake waiters on the event device when we actually post
an EV_SYN/SYN_REPORT to the queue. Otherwise we end up making waiting
threads runnable only to go right back to sleep because the device
still isn't readable.

Reported-by: Jeffrey Brown 
Signed-off-by: Dmitry Torokhov

Input: remove useless synchronize_rcu() calls

2011-05-12T15:28:57+00:00

There is no need to call synchronize_rcu() after a list insertion,
or a NULL->ptr assignment.

However, the reverse operations do need this call.

Signed-off-by: Eric Dumazet 
Signed-off-by: Dmitry Torokhov

Input: evdev - only signal polls on full packets

2011-04-27T05:16:38+00:00

This patch modifies evdev so that it only becomes readable when
the buffer contains an EV_SYN/SYN_REPORT event.

On SMP systems, it is possible for an evdev client blocked on poll()
to wake up and read events from the evdev ring buffer at the same
rate as they are enqueued.  This can result in high CPU usage,
particularly for MT devices, because the client ends up reading
events one at a time instead of reading complete packets.

We eliminate this problem by making the device readable only when
the buffer contains at least one complete packet.  This causes
clients to block until the entire packet is available.

Signed-off-by: Jeff Brown 
Signed-off-by: Dmitry Torokhov

Input: evdev - indicate buffer overrun with SYN_DROPPED

2011-04-13T06:35:24+00:00

Add a new EV_SYN code, SYN_DROPPED, to inform the client when input
events have been dropped from the evdev input buffer due to a
buffer overrun.  The client should use this event as a hint to
reset its state or ignore all following events until the next
packet begins.

Signed-off-by: Jeff Brown 
[dtor@mail.ru: Implement Henrik's suggestion and drop old events in
 case of overflow.]
Signed-off-by: Dmitry Torokhov

Input: evdev - fix evdev_write return value on partial writes

2011-02-27T09:52:53+00:00

As was recently brought up on the busybox list
(http://lists.busybox.net/pipermail/busybox/2011-January/074565.html),
evdev_write doesn't properly check the count argument, which will
lead to a return value > count on partial writes if the remaining bytes
are accessible - causing userspace confusion.

Fix it by only handling each full input_event structure and return -EINVAL
if less than 1 struct was written, similar to how it is done in evdev_read.

Reported-by: Baruch Siach 
Signed-off-by: Peter Korsgaard 
Acked-by: Henrik Rydberg 
Signed-off-by: Dmitry Torokhov