At Wed, 15 Oct 2014 14:21:34 -0600, Shuah Khan wrote: > > 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. We can create a small module depending on CONFIG_MEDIA. But it'll be rather a question of the size. If it's reasonably small and generic enough, it's worth to put into lib/*, I think. Takashi -- 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
