On 10/15/2014 10:48 AM, Takashi Iwai wrote: > At Tue, 14 Oct 2014 08:58:36 -0600, > Shuah Khan wrote: >> >> Add media token device resource framework to allow sharing >> resources such as tuner, dma, audio etc. across media drivers >> and non-media sound drivers that control media hardware. The >> Media token resource is created at the main struct device that >> is common to all drivers that claim various pieces of the main >> media device, which allows them to find the resource using the >> main struct device. As an example, digital, analog, and >> snd-usb-audio drivers can use the media token resource API >> using the main struct device for the interface the media device >> is attached to. >> >> This patch series consists of media token resource framework >> and changes to use it in dvb-core, v4l2-core, au0828 driver, >> and snd-usb-audio driver. >> >> With these changes dvb and v4l2 can share the tuner without >> disrupting each other. Used tvtime, xawtv, kaffeine, and vlc, >> vlc audio capture option, arecord/aplay during development to >> identify v4l2 vb2 and vb1 ioctls and file operations that >> disrupt the digital stream and would require changes to check >> tuner ownership prior to changing the tuner configuration. >> vb2 changes are made in the v4l2-core and vb1 changes are made >> in the au0828 driver to encourage porting drivers to vb2 to >> advantage of the new media token resource framework with changes >> in the core. >> >> In this patch v2 series, fixed problems identified in the >> patch v1 series. Important ones are changing snd-usb-audio >> to use media tokens, holding tuner lock in VIDIOC_ENUMINPUT, >> and VIDIOC_QUERYSTD. > > Just took a quick glance over the patches, and my first concern is why > this has to be lib/*. This means it's always built-in as long as this > config is enabled (and will be so on distro kernel) even if it's not > used at all. > Right this module gets built when CONFIG_MEDIA_SUPPORT is enabled and stubs are in place when it is not enabled. The intent is for this feature to be enabled by default when media support is enabled. When a driver doesn't create the resource, it will simply not find it and for drivers like snd-usb-audio that aren't tried to media support, the stubs are in place and feature is essentially disabled. I picked lib so this module can be included in non-media drivers e.g: snd-usb-audio. Does this help explain the design? I didn't want to introduce a new config for this feature. If lib isn't right place, could you recommend another one that makes this modules available to non-media drivers? moving isn't a problem. thanks, -- Shuah -- Shuah Khan Sr. Linux Kernel Developer Samsung Research America (Silicon Valley) shuahkh@xxxxxxxxxxxxxxx | (970) 217-8978 -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
