Kernel 6.18 bug breaks pwm-ir-tx IR blaster on Raspberry Pi

In the 6.18 Raspberry Pi kernel, the pwm-ir-tx driver sends all signal edges within 7 microseconds instead of the intended 100 ms bursts due to an inverted loop condition, while ir-ctl still exits 0. Workaround: use dtoverlay=gpio-ir-tx on the same pin.

• A 100/100/100 ms test signal was sent in 7 µs instead of 300 ms
• ir-ctl --send returns 0 and ~350 ms, hiding the failure
• Cause is commit 44d7fb8acdf8, which inverted the loop condition in v6.18
• Workaround: dtoverlay=gpio-ir-tx, gpio_pin=18 instead of pwm-ir-tx