Re: [PATCH v3 0/2] i2c: imx: fix SMBus block-read of 0 locking the bus

From: Wolfram Sang

Date: Tue Jul 14 2026 - 11:46:24 EST


On Mon, Jul 13, 2026 at 08:11:58PM +0200, Vincent Jardin wrote:
> i2c-imx rejects an SMBus Block Read byte count of 0 (valid per SMBus 3.1
> 6.5.7) as -EPROTO and returns without emitting a NACK + STOP, leaving the
> target holding SDA so the bus stays stuck until a power cycle.

Bigger picture: Linux does not support SMBus3 which also allows byte
counts of up to 255. I started sketching support for all that but could
never implement it.

That being said, despite no SMBus3 support, it should not hang the bus
like here.