Add feedback not based on samples used, but on buffers filled - idea
being we can do "PID" (someone who has actually implemented Real PID
could probably rewrite the calculation) based on how many buffers
we have filled versus the ideal buffer filled level (16).
Feedback is based on a historical average of the last two feedback
intervals.
This feedback math is done as fixed-point math to keep floats out of core. Note that a couple division operations needed to be strategically staged to avoid overflow or truncation.
Floats are still used for debug screen printout.
Also fixed a typo in the definition of usb_audio_control_request()
Host:
Linux: works
MacOS: works
Windows: Feedback does not work! It appears that Windows may not
support asynchronous devices at all. Playback may "work",
but results will vary as the number of buffers filled will
drift over time.
Change-Id: I027feb16705e6e46c1144b1d08920b53de42cb26
Original commit credit to Amaury Pouly, Moshe Piekarski
Pushed across the finish line by Dana Conrad
To enable, see setting under General Settings --> System --> USB-DAC.
On devices with few endpoints, this may not work while HID and/or
mass storage is enabled.
Adds new dedicated mixer channel.
setting usb-dac can have values:
- never (0)
- always (1)
- while_charge_only (2)
- while_mass_storage (3)
Relevant devices are DWC2 and ARC usb controller devices. That being:
x1000 Native targets (m3k, erosqnative, q1, others...?),
sansac200, creativezenxfi2, vibe500, ipodmini2g,
ipod4g, creativezenxfi, creativezenxfi3, sansaview, ipodcolor,
creativezenxfistyle, samsungypz5, sansafuzeplus, iriverh10_5gb,
tatungtpj1022, gigabeats, faketarget, samsungyh820, gogearhdd1630, samsungyh925, ipodmini1g, ipodvideo, creativezenmozaic, sonynwze370, creativezen, gogearsa9200, gogearhdd6330, sonynwze360, sansae200, mrobe100, iriverh10, creativezenv, ipodnano1g, samsungyh920
USB Driver-wise, it should be noted that this patch requires some
slight changes:
- proper blocking on control OUT transfers, to make sure the data is
received *before* using it, the usb_core should probably use that too
- drivers can now support interface alternate settings
- drivers can be notified of completion by a new fast handler, which
is called directly from the driver; this is is necessary for
isochronous transfers because going through the usb queue is way too
slow
Designware changes:
- enable for USBOTG_DESIGNWARE
- set maxpacketsize to 1023 for ISO endpoints
Change-Id: I570871884a4e4820b4312b203b07701f06ecacc6
