Hi Aniket, Thanks for addressing previous comments.
On 7/10/2026 9:40 PM, Aniket Randive wrote:
The driver uses a static XFER_TIMEOUT of HZ (1 second) for all transfers regardless of message length or bus frequency, causing unnecessary delays on error paths.
Compute the timeout dynamically from message length and bus frequency with a 10x safety margin over the theoretical wire time. Add a 300ms floor to budget for I2C clock stretching, where a slave may hold SCL low indefinitely during internal processing. This detects real hangs
not only internal processing but it may go bad holding SCL low indefinitely.
3x faster than the old 1s static timeout.
Meaning, in such case/scenario, don't need to wait till fixes timeout. I guess, 3x faster is relative to the 1 sec, but for larger data and slower frequency it may not be 3x. Hence, correct it accordingly.
For GPI multi-descriptor transfers, use the maximum message length across all queued messages as the per-completion timeout.
Signed-off-by: Aniket Randive aniket.randive@oss.qualcomm.com
Changes in v4:
- As per konrad suggestion used mult_frac() for bit_usec to avoid intermediate
Do not keep space before starting, directly start with "- As per....."
overflow on 32-bit targets.
- Updated the commit message and added a driver comment explaining the rationale for the 0.3-second minimum timeout floor value.
drivers/i2c/busses/i2c-qcom-geni.c | 46 +++++++++++++++++++++++------- 1 file changed, 36 insertions(+), 10 deletions(-)
diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/i2c-qcom-geni.c index 96dbf04138be..c5c3adc8ec77 100644 --- a/drivers/i2c/busses/i2c-qcom-geni.c +++ b/drivers/i2c/busses/i2c-qcom-geni.c @@ -74,9 +74,13 @@ enum geni_i2c_err_code { #define PACKING_BYTES_PW 4 #define ABORT_TIMEOUT HZ -#define XFER_TIMEOUT HZ #define RST_TIMEOUT HZ +/* 9 bits per byte (8 data + 1 ACK), 10x safety margin */ +#define I2C_TIMEOUT_SAFETY_COEFFICIENT 10
Add a line space to make it look clean
+/* 300ms floor: budget for clock stretching; slave may hold SCL low indefinitely */
Already explained in commit log, can remove second part.
+#define I2C_TIMEOUT_MIN_USEC 300000
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