The USB control messages require DMA to work. We cannot pass
a stack-allocated buffer, as it is not warranted that the
stack would be into a DMA enabled area.
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
kmalloc will print enough information in case of failure.
Signed-off-by: Wolfram Sang <wsa-dev@sang-engineering.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
cpia2_usb_disconnect() seems to be missing a memory barrier which might
cause the waker to not notice the waiter and miss sending a wake_up as
in the following figure.
cpia2_usb_disconnect sync
------------------------------------------------------------------------
mutex_unlock(&cam->v4l2_lock);
if (waitqueue_active(&cam->wq_stream))
/* The CPU might reorder the test for
the waitqueue up here, before
prior writes complete */
/* wait_event_interruptible */
/* __wait_event_interruptible */
/* ___wait_event */
long __int = prepare_to_wait_event(
&wq, &__wait, state);
if (!cam->streaming ||
frame->status == FRAME_READY)
cam->curbuff->status = FRAME_READY;
cam->curbuff->length = 0;
schedule()
------------------------------------------------------------------------
The attached patch removes the call to waitqueue_active() leaving just
wake_up() behind. This fixes the problem because the call to
spin_lock_irqsave() in wake_up() will be an ACQUIRE operation.
I found this issue when I was looking through the linux source code
for places calling waitqueue_active() before wake_up*(), but without
preceding memory barriers, after sending a patch to fix a similar
issue in drivers/tty/n_tty.c (Details about the original issue can be
found here: https://lkml.org/lkml/2015/9/28/849).
Signed-off-by: Kosuke Tatsukawa <tatsu@ab.jp.nec.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
The variable frame_ready is only assigned the values true and false.
Change its type to bool.
The simplified semantic patch that find this problem is as
follows (http://coccinelle.lip6.fr/):
@exists@
type T;
identifier b;
@@
- T
+ bool
b = ...;
... when any
b = \(true\|false\)
Signed-off-by: Peter Senna Tschudin <peter.senna@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Convert drivers using wall clock time (CLOCK_REALTIME) to timestamp from the
monotonic timer (CLOCK_MONOTONIC).
Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Rename all USB drivers with their own directory under
drivers/media/video into drivers/media/usb and update the
building system.
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
