QR code dialog buttons not working properly

[onvej-sl]

Neither of the buttons on the QR code dialog is responding properly. I have to tap it multiple times to invoke an action.

Firmware 2.3.1. It affects only device (not emulator).

[tsusanka]

@trezor/qa could you retest please?

[bosomt]

@tsusanka tested, this is happening with every version of FW for a long time.

Tested it now with 2.3.1 and it's sometime happens and sometime now.

I can record video when i press QR/Address button or OK button 10 times and it won't happen.
And sometimes it won't respond 10 times in row.

i can show you at Monday in office.

[sorooris]

@tsusanka
QA NOK
Wallet: prod, commit here
Browser: any (tested Chromium)

Device fw versions:

• 2.3.1 c6b2580
• 2.3.0 0b7a844
• 2.1.8 8eb6ce0

Note: Confirming issue with both buttons - however, there is an inconsistent occurence of the described issue as @bosomt describes above.

[bosomt]

updated with new information.

QA NOK

Retested with following results:

2.1.1 7af1d58 OK
2.1.4 6a1a02c NOK

note: there were no public releases between 2.1.1 and 2.1.4

[andrewkozlik]

The bug is caused by a missing repaint check in Qr::on_render(), so the device keeps redrawing the QR code. It was effectively introduced in 3653432, although the distal cause was probably the fact that the function was already missing self.tainted = True before that.

There are several other on_render() methods where the repaint check is missing. Most of them have some sort of animation like ui.display.loader() or pulsating arrows, so in those cases it's intentional. In the Homescreen and Lockscreen classes the repaint check is handled in the dispatch method. So Qr::on_render() seems to be the only problematic case.

[bosomt]

QA OK
now I have 100% success when changing QR/address via touchscreen button

tested with current master f382f77 2.3.2
and current wallet Git Commit: 1f09c65d25eaf01aa3da804dfedf765b588d3559