usb: device_next: add device configuration change notification #76264
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jfischer-no
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subsys/usb/device_next/usbd_ch9.c
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The fact that notifications are asynchronous make this somewhat fragile, because the connection speed can change between the publish and handling. If the device disconnects though (which is mandatory for the speed to change) any stale configuration notifications are no longer relevant anyway.
I consider this as a example to where the notifications should be synchronous.
Notify only if the device configuration has changed. Pass only the configuration value as the message status, the actual device speed can be obtained with usbd_bus_speed(). Signed-off-by: Johann Fischer <[email protected]>
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tmon-nordic
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Approve, but I think we should revisit having synchronous notifications later. The more I think about potential issues we might face later due to asynchronous notification, the more I think zbus would be appropriate (as it leaves the choice between synchronous/asynchronous to application developer).
You have not expressed any specific problems with what you call "asynchronous" behavior. The existing implementation has no known drawbacks, is simple and efficient. There is no reason to add something bloated, complicated, and with unpredictable behavior, and therefore there will never be notification with ZBUS in USB. |
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Notify only if the device configuration has changed. Pass only the configuration value as the message status, the actual device speed can be obtained with usbd_bus_speed().