Add a managed token resource that can be created at device level which can be used as a large grain lock by diverse group of drivers such as the media drivers that share a resource.
Token resource manages a unique named string resource which is derived from common bus_name, and hardware address fields from the struct device. au0828 is changed to use token devres as a large locking for exclusive access to tuner function. A new tuner_tkn field is added to struct au0828_dev. Tuner token is created from au0828 probe() and destroyed from disconnect(). Two new routines au0828_create_token_resources() and au0828_destroy_token_resources() create and destroy the tuner token. au0828-dvb exports the tuner token to dvb-frontend when it registers the digital frontend using the tuner_tkn field in struct dvb_frontend. au0828-video exports the tuner token to v4l2-core when it registers the analog function using tuner_tkn field in struct video_device. Before this change: - digital tv app disrupts an active analog app when it tries to use the tuner e.g: tvtime analog video stream stops when kaffeine starts - analog tv app disrupts another analog app when it tries to use the tuner e.g: tvtime audio glitches when xawtv starts and vice versa. - analog tv app disrupts an active digital app when it tries to use the tuner e.g: kaffeine digital stream stops when tvtime starts - digital tv app disrupts another digital tv app when it tries to use the tuner e.g: kaffeine digital stream stops when vlc starts and vice versa After this change: - digital tv app detects tuner is busy without disrupting the active app. - analog tv app detects tuner is busy without disrupting the active analog app. - analog tv app detects tuner is busy without disrupting the active digital app. - digital tv app detects tuner is busy without disrupting the active digital app. Requesting feedback on any use-cases I missed and overall approach to solving the contention between media functions. Shuah Khan (4): drivers/base: add managed token dev resource media: dvb-fe changes to use tuner token media: v4l2-core changes to use tuner token media: au0828 changes to use token devres for tuner access drivers/base/Makefile | 2 +- drivers/base/token_devres.c | 134 +++++++++++++++++++++++++++++++ drivers/media/dvb-core/dvb_frontend.c | 21 +++++ drivers/media/dvb-core/dvb_frontend.h | 1 + drivers/media/usb/au0828/au0828-core.c | 42 ++++++++++ drivers/media/usb/au0828/au0828-dvb.c | 1 + drivers/media/usb/au0828/au0828-video.c | 4 + drivers/media/usb/au0828/au0828.h | 4 + drivers/media/v4l2-core/v4l2-dev.c | 23 +++++- include/linux/token_devres.h | 19 +++++ include/media/v4l2-dev.h | 1 + 11 files changed, 250 insertions(+), 2 deletions(-) create mode 100644 drivers/base/token_devres.c create mode 100644 include/linux/token_devres.h -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
