When USB was disconnected, we were freeing our audio_dev struct in audio_unbind
before the audio system had cleaned up, resulting in a hang in audio_pcm_close.
We now statically allocate the audio_dev struct to avoid this problem.
Change-Id: I58ad21eaa20dcf4aa74ee614ef3b6ed2c91d52a1
Signed-off-by: Mike Lockwood <lockwood@google.com>
This was detected because events with invalid types were arriving
to userspace.
The code before this patch would only work for the first event in the
queue (when uhid->tail is 0).
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@openbossa.org>
Reviewed-by: David Herrmann <dh.herrmann@googlemail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
gcc is giving me:
drivers/hid/uhid.c: In function ‘uhid_hid_get_raw’:
drivers/hid/uhid.c:157: warning: ‘len’ may be used uninitialized in this function
which is clearly bogus, as
- when used as memcpy() argument, it's initialized properly
- the code is structured in a way that either 'ret' or 'len'
is always initialized, so the return statement always has
an initialized value.
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This adds an example user-space program that emulates a 3 button mouse
with wheel. It detects keyboard presses and moves the mouse accordingly.
It register a fake HID device to feed the raw HID reports into the kernel.
In this example, you could use uinput to get the same result, but this
shows how to get the same behavior with uhid so you don't need HID parsers
in user-space.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This describes the protocol used by uhid for user-space applications. It
describes the details like non-blocking I/O and readv/writev for multiple
events per syscall.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
HID standard allows sending a feature request to the device which is
answered by an HID report. uhid implements this by sending a UHID_FEATURE
event to user-space which then must answer with UHID_FEATURE_ANSWER. If it
doesn't do this in a timely manner, the request is discarded silently.
We serialize the feature requests, that is, there is always only a single
active feature-request sent to user-space, other requests have to wait.
HIDP and USB-HID do it the same way.
Because we discard feature-requests silently, we must make sure to match
a response to the corresponding request. We use sequence-IDs for this so
user-space must copy the ID from the request into the answer.
Feature-answers are ignored if they do not contain the same ID as the
currently pending feature request.
Internally, we must make sure that feature-requests are synchronized with
UHID_DESTROY and close() events. We must not dead-lock when closing the
HID device, either, so we have to use separate locks.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Some drivers that use non-standard HID features require raw output reports
sent to the device. We now forward these requests directly to user-space
so the transport-level driver can correctly send it to the device or
handle it correspondingly.
There is no way to signal back whether the transmission was successful,
moreover, there might be lots of messages coming out from the driver
flushing the output-queue. However, there is currently no driver that
causes this so we are safe. If some drivers need to transmit lots of data
this way, we need a method to synchronize this and can implement another
UHID_OUTPUT_SYNC event.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
If the hid-driver wants to send standardized data to the device it uses a
linux input_event. We forward this to the user-space transport-level
driver so they can perform the requested action on the device.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
HID core notifies us with *_open/*_close callbacks when there is an actual
user of our device. We forward these to user-space so they can react on
this. This allows user-space to skip I/O unless they receive an OPEN
event. When they receive a CLOSE event they can stop I/O again to save
energy.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
We send UHID_START and UHID_STOP events to user-space when the HID core
starts/stops the device. This notifies user-space about driver readiness
and data-I/O can start now.
This directly forwards the callbacks from hid-core to user-space.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
When the uhid_hid_parse callback is called we simply forward it to
hid_parse_report() with the data that we got in the UHID_CREATE event.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This adds a new event type UHID_INPUT which allows user-space to feed raw
HID reports into the HID subsystem. We copy the data into kernel memory
and directly feed it into the HID core.
There is no error handling of the events couldn't be parsed so user-space
should consider all events successfull unless read() returns an error.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
UHID_CREATE and UHID_DESTROY are used to create and destroy a device on an
open uhid char-device. Internally, we allocate and register an HID device
with the HID core and immediately start the device. From now on events may
be received or sent to the device.
The UHID_CREATE event has a payload similar to the data used by
Bluetooth-HIDP when creating a new connection.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Similar to read() you can only write() a single event with one call to an
uhid device. To write multiple events use writev() which is supported by
uhid.
We currently always return -EOPNOTSUPP but other events will be added in
later patches.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
User-space can use read() to get a single event from uhid devices. read()
does never return multiple events. This allows us to extend the event
structure and still keep backwards compatibility.
If user-space wants to get multiple events in one syscall, they should use
the readv()/writev() syscalls which are supported by uhid.
This introduces a new lock which helps us synchronizing simultaneous reads
from user-space. We also correctly return -EINVAL/-EFAULT only on errors
and retry the read() when some other thread captured the event faster than
we did.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
As long as the internal buffer is not empty, we return POLLIN to
user-space.
uhid->head and uhid->tail are no atomics so the comparison may return
inexact results. However, this doesn't matter here as user-space would
need to poll() in two threads simultaneously to trigger this. And in this
case it doesn't matter if a cached result is returned or the exact new
result as user-space does not know which thread returns first from poll()
and the following read(). So it is safe to compare the values without
locking.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
When receiving messages from the HID subsystem, we need to process them
and store them in an internal buffer so user-space can read() on the char
device to retrieve the messages.
This adds a static buffer for 32 messages to each uhid device. Each
message is dynamically allocated so the uhid_device structure does not get
too big.
uhid_queue() adds a message to the buffer. If the buffer is full, the
message is discarded. uhid_queue_event() is an helper for messages without
payload.
This also adds a public header: uhid.h. It contains the declarations for
the user-space API. It is built around "struct uhid_event" which contains
a type field which specifies the event type and each event can then add a
variable-length payload. For now, there is only a dummy event but later
patches will add new event types and payloads.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This adds a dummy driver that will support user-space I/O drivers for the
HID subsystem. This allows to write transport-level drivers like USB-HID
and Bluetooth-HID in user-space.
Low-Energy Bluetooth needs this to feed HID data that is parsed in
user-space back into the kernel.
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
"echo -e" is a GNU extension. When cross-compiling the kernel on a
BSD-like operating system (Mac OS X in my case), this doesn't work.
One could install a GNU version of echo, put that in the $PATH before
the system echo and use "/usr/bin/env echo", but the solution with
printf is simpler.
Since it is no disadvantage on Linux, I hope that gets accepted even if
cross-compiling the Linux kernel on another Unix operating system is
quite a rare use case.
Signed-off-by: Bernhard Walle <bernhard@bwalle.de>
Andreas Bießmann <andreas@biessmann.de>
Signed-off-by: Michal Marek <mmarek@suse.cz>
BZ: 35303
Google patched the idle loop for x86-64 (commit 1fd57f722c) and for ARM
(commit 41fa406c26), but they forgot x86-32.
This is preventing their interactive governor from upshifting CPU
frequencies in intel's SOC platforms (e.g. Medfield, etc.).
Fixing that.
NOTE: The notifier calls are not located in the same exact place in the
idle loop for x86-64 and ARM. The notifier is called inside the
`while(!need_resched)' loop in x86-64 and outside of it in ARM. Since
Google has likely tuned this governor for ARM, leaving it as in ARM.
Change-Id: Ibefd0c8f08e4b4c24c4a5c32dcdc574f9090b2b9
Signed-off-by: German Monroy <german.monroy@intel.com>
The ext4_error() function is missing a call to save_error_info().
Since this is the function which marks the file system as containing
an error, this oversight (which was introduced in 2.6.36) is quite
significant, and should be backported to older stable kernels with
high urgency.
Change-Id: Ia1eb8d91f37ceb67faf3b79d6bc79b899f1d6bfc
Reported-by: Ken Sumrall <ksumrall@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: ksumrall@google.com
Cc: stable@kernel.org
Signed-off-by: Ken Sumrall <ksumrall@android.com>
Increase max packet size and clean up timing logic so we can better
recover from not getting an interrupt in time for a SOF.
Signed-off-by: Mike Lockwood <lockwood@google.com>
