Aurora-QIU0 opened a new pull request, #20165:
URL: https://github.com/apache/nuttx/pull/20165
## Summary
clock_t is unsigned unless CONFIG_SYSTEM_TIME64 is set (see sys/types.h). The
comparison in esp_i2c_polling_waitdone():
while (current - timeout < 0 && priv->error == 0)
underflows to a large positive value, so the condition is always false and
the
loop body never runs. status keeps its initial value of zero and the function
returns OK without ever waiting for the transfer.
Under CONFIG_I2C_POLLED every transfer therefore reports completion
immediately:
no timeout is raised and register reads return whatever the RX FIFO happens
to
contain. This is a silent "false success" - no error is reported.
Cast the difference to int32_t to restore the intended signed comparison. The
result stays correct across counter wrap since the timeout is much shorter
than
the counter range.
## Impact
- New feature? NO
- Impact on user? NO (only corrects polling wait timeout)
- Impact on build? NO
- Impact on hardware? YES (risc-v/espressif I2C, polling mode)
- Impact on documentation? NO
- Impact on security? NO
- Impact on compatibility? NO
## Testing
Validated on real hardware during an ESP32-P4 board bring-up. Before the fix,
I2C reads returned garbage (0x2f) with ret=0 - a mathematically impossible
combination (status==0 yet success). After the fix, the GT911 touch
controller
enumerated correctly and register reads returned real values.
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