Re: [PATCH] hwmon: (sg2042-mcu) reject short uptime reads

On Sun, Aug 02 2026, Guenter Roeck wrote:

> Please refrain from sending fixes for non-issues.

You are right. Please drop it.

I checked what i2c_smbus_read_i2c_block_data() returns without checking
which protocol it runs, and the two block protocols do not behave the
same. In i2c_smbus_xfer_emulated(), I2C_SMBUS_BLOCK_DATA sets
I2C_M_RECV_LEN and reads back with

	memcpy(data->block, msg[1].buf, msg[1].buf[0] + 1);

so there the device supplies the count and a short reply is a real
thing. I2C_SMBUS_I2C_BLOCK_DATA, which is what this call uses, sets no
I2C_M_RECV_LEN, sends msg[1].len = data->block[0] and reads back with

	memcpy(data->block + 1, msg[1].buf, data->block[0]);

which never touches data->block[0]. An I2C block read carries no length
byte on the wire, so nothing can shorten it, and a transfer that is cut
short fails with an errno rather than returning a smaller count. time_val
is fully written whenever the call succeeds.

I should have read that before sending, rather than reasoning from the
return value alone. Sorry for the noise, and for the stable Cc on top of
it.

--
Ali