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726daf6baf
do_poll()/do_select() seem to set the _qproc member of poll_table to NULL the first time they are called on a given table, making subsequent calls of poll_wait() on that table no-ops. This is a problem for mem2mem which calls poll_wait() on the V4L2 queues' waitqueues only when a queue-related event is requested, which may not necessarily be the case during the first poll. For instance, a stateful decoder is typically only interested in EPOLLPRI events when it starts, and will switch to listening to both EPOLLPRI and EPOLLIN after receiving the initial resolution change event and configuring the CAPTURE queue. However by the time that switch happens and v4l2_m2m_poll_for_data() is called for the first time, poll_wait() has become a no-op and the V4L2 queues waitqueues thus cannot be registered. Fix this by moving the registration to v4l2_m2m_poll() and do it whether or not one of the queue-related events are requested. Signed-off-by: Alexandre Courbot <gnurou@gmail.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> |
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| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.