HID Keyboard: handle delayed and terminated connections #1929
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@dhalbert : Would you mind looking at this?
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Thanks for the PR. It is a long holiday weekend in the US; I will take a look at this next week, I hope. |
| keyboard = Keyboard(usb_hid.devices) | ||
| keyboard_layout = KeyboardLayoutUS(keyboard) # We're in the US :) | ||
| break # successfully connected, leave the connection loop | ||
| except: |
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this will also cach KeyboardInterrupt and many other errors you don't want to catch and hide from the user
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That's why I asked Dan to review. He probably knows the execption type(s) to catch.
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| time.sleep(0.01) | ||
| time.sleep(0.01) | ||
| except: |
| # The keyboard object! | ||
| keyboard = Keyboard(usb_hid.devices) | ||
| keyboard_layout = KeyboardLayoutUS(keyboard) # We're in the US :) | ||
| break # successfully connected, leave the connection loop |
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you probably want this break in an else clause of the try
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Personally I prefer the break at this position as it's clearer. I have moved the KeyboardLaoyutUS code out of try/except, though. I think it can't fail.
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This very old PR has lain fallow, sorry. I recently revisited the same issue. Nowadays another, probably simpler, way to check would be to use |
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Sure, feel free to close this one, probably after posting a link to the new method. Would be great to have also a method to fix adafruit/circuitpython#5380 . |
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(Finally) the adafruit_hid library now checks for |
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Well, with the other, merged PR the initial connection will not timeout. So, a delayed connection does not need to be handled any more. But what happens when the PC shuts down with the USB ports remaining powered or when it goes to standby. Probably the connection will then fail at some point. So the try/except around the main loop is still required, right? See also adafruit/circuitpython#5380 . This probably needs some controlled disconnection as well. A solution for this would probably remove the need for try/except for terminated connections. |
I am worried about that change that will likely break my ultimate mouse jiggle. In my code I actively wait for the USB to be there while blinking an LED to warn about a problem. That is the behavior if you plug your mouse jiggler in a USB charger... it is also what is happening when your computer boot. To answer @DietmarSchwertberger I am not sure what is happening at the end, when you turn off your operating system, but the USB port is still powered because it is a charging port. In my code I force a reload on error, so when that occurs, I go back to the initial loop of blink warning. I'll stop complaining here and try to complain on the usb_hid library about that breaking change. :-) |
The example code is used on many projects, but actually it fails on many occasions, e.g. when shutting down and re-starting a PC.
The modifications handle connection problems. They will try until a successful connection is made and when it is dropped, they will re-try.
Unfortunately I don't know which exception types are thrown exactly. So at the moment I have just added
except:I could not test exactly this code, as my hardware is different.
Also, it might be a good idea to add example code for
boot.py: