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Jared Kangas
34d6d448e1
JIRA: https://redhat.atlassian.net/browse/RHEL-248519 commit 07fd9385f0d87dff4b34f355f68adf701080cb24 Author: Vincent Jardin <vjardin@free.fr> Date: Mon Jul 13 20:12:00 2026 +0200 i2c: imx: fix locked bus on SMBus block-read of 0 (IRQ) SMBus 3.1 6.5.7 allows a Block Read byte count of 0, but the interrupt-driven block-read state machine rejects it as -EPROTO. Worse, it returns without a NACK+STOP: the next receive cycle has already started, so the target keeps holding SDA and the bus stays stuck until a power cycle of this i2c controller. Accept count=0: NACK the in-flight dummy byte (TXAK) and set msg->len to 2 so i2c_imx_isr_read_continue() emits STOP via its normal last-byte path. The dummy byte is discarded; block-read callers only consume buf[0..count-1]. Reading I2DR has likewise already armed the next byte on the count > I2C_SMBUS_BLOCK_MAX error path, so NACK it (TXAK) before aborting with -EPROTO; otherwise the failing transfer's STOP cannot complete and the bus stays held. The atomic path regressed earlier (v3.16) and is fixed separately; this patch covers only the v6.13 state-machine rework. Fixes: 5f5c2d4579ca ("i2c: imx: prevent rescheduling in non dma mode") Signed-off-by: Vincent Jardin <vjardin@free.fr> Cc: <stable@vger.kernel.org> # v6.13+ Acked-by: Oleksij Rempel <o.rempel@pengutronix.de> Acked-by: Carlos Song <carlos.song@nxp.com> Reviewed-by: Stefan Eichenberger <eichest@gmail.com> Signed-off-by: Andi Shyti <andi.shyti@kernel.org> Link: https://lore.kernel.org/r/20260713-for-upstream-i2c-lx2160-fix-v1-v3-2-073ac9e103a5@free.fr Signed-off-by: Jared Kangas <jkangas@redhat.com>