Media Device Allocator API to allows multiple drivers share a media device. Using this API, drivers can allocate a media device with the shared struct device as the key. Once the media device is allocated by a driver, other drivers can get a reference to it. The media device is released when all the references are released.
Patches 0001 and 0002 are rebased to 4.9-rc7. Patch 0003 for snd-usb-audio is a rebase of the patch that was tested with the original Media Device Allocator patch series.
snd-usb-audio patch includes the fixes found during 4.7-rc1 time in the original snd-usb-audio patch.
Changes to patches in this series: Changes to patch 0001 since v5: (comments from Mauro and Sakari) - Removed struct device from media_device_instance. mdev.dev is used instead. - Added documentation.
Changes to patch 0002: - No changes since patch v2, applies cleanly on top of the following: media: Protect enable_source and disable_source handler code paths https://lkml.org/lkml/2016/11/29/1001
Changes to patch 0003: - Changed to hold graph_mutex to check and call enable_source and disable_source handlers - to match au0828 doing the same in: media: Protect enable_source and disable_source handler code paths https://lkml.org/lkml/2016/11/29/1001
Changes to patch 0001 since v4: - Addressed Sakari's review comments with the exception of opting to not introduce media_device_usb_allocate() macro, and to not add a new routine to find media device instance to avoid a one line check.
Changes to patch 0001 since v3: - Fixed undefined reference to `__media_device_usb_init compile error when CONFIG_USB is disabled. - Fixed kernel paging error when accessing /dev/mediaX after rmmod of the module that owns the media_device. The fix bumps the reference count for the owner when second driver comes along to share the media_device. If au0828 owns the media_device, then snd_usb_audio will bump the refcount for au0828, so it won't get deleted and vice versa.
Changes to patch 0002 since v2: - Updated media_device_delete() to pass in module name.
Changes to patch 0003 since the last version in 4.7-rc1: - Included fixes to bugs found during testing. - Updated to use the Media Allocator API.
This patch series has been tested with au0828 and snd-usb-audio drivers. Ran bind and unbind loop tests on each driver with mc_nextgen_test and media_device_test app loop tests while checking lsmod and dmesg.
Please refer to tools/testing/selftests/media_tests/regression_test.txt for testing done on this series.
Shuah Khan (3): media: Media Device Allocator API media: change au0828 to use Media Device Allocator API sound/usb: Use Media Controller API to share media resources
Documentation/media/kapi/mc-core.rst | 37 ++++ drivers/media/Makefile | 3 +- drivers/media/media-dev-allocator.c | 133 ++++++++++++++ drivers/media/usb/au0828/au0828-core.c | 12 +- drivers/media/usb/au0828/au0828.h | 1 + include/media/media-dev-allocator.h | 54 ++++++ sound/usb/Kconfig | 4 + sound/usb/Makefile | 2 + sound/usb/card.c | 14 ++ sound/usb/card.h | 3 + sound/usb/media.c | 326 +++++++++++++++++++++++++++++++++ sound/usb/media.h | 73 ++++++++ sound/usb/mixer.h | 3 + sound/usb/pcm.c | 28 ++- sound/usb/quirks-table.h | 1 + sound/usb/stream.c | 2 + sound/usb/usbaudio.h | 6 + 17 files changed, 688 insertions(+), 14 deletions(-) create mode 100644 drivers/media/media-dev-allocator.c create mode 100644 include/media/media-dev-allocator.h create mode 100644 sound/usb/media.c create mode 100644 sound/usb/media.h