Re: [PATCH v5 06/11] i2c: rtl9300: remove SMBus Quick operation support

[Sven Eckelmann <sven@narfation.org>]

[-- Attachment #1: Type: text/plain, Size: 1128 bytes --]

On Sunday, 10 August 2025 00:07:07 CEST Jonas Jelonek wrote:
[...]
> The current implementation of SMBus Quick operation passes a length of
> 0 (which is actually invalid). Before the fix of a bug in a previous
> commit, this led to a read operation of 16 bytes from any register (the
> one of a former transaction or any other value.
> 
> Although there are currently no reports of actual issues this caused.
> However, as an example, i2cdetect by default uses Quick Write operation
> to probe the bus and this may already write anything to some register
> of a device, causing unintended behaviour. This could be the cause of a
> recent brick of one of my DAC cables where there was a checksum mismatch
> of the EEPROM after having run 'i2cdetect -l' before.
[...]

Nice find. I've actually observed odd behavior after/during probing and 
attributed it only to the other problems (especially the low timeout + missing 
check) we found and never did a deep dive to figure out what happened on the 
bus during the probe. Possible that this could be related.

Reviewed-by: Sven Eckelmann <sven@narfation.org>

Kind regards,
	Sven

[-- Attachment #2: This is a digitally signed message part. --]
[-- Type: application/pgp-signature, Size: 228 bytes --]