On 05/19/2017 01:06 PM, Ard Biesheuvel wrote:
On 19 May 2017 at 11:01, Jarkko Nikula <jarkko.nikula@xxxxxxxxxxxxxxx> wrote:
On 05/19/2017 11:56 AM, Ard Biesheuvel wrote:
Commit bd698d24b1b57 ("i2c: designware: Get selected speed mode
sda-hold-time via ACPI") updated the logic that reads the timing
parameters for various I2C bus rates from the DSDT, to only read
the timing parameters for the currently selected mode.
This causes a WARN_ON() splat on platforms that legally omit the clock
frequency from the ACPI description, because in the new situation, the
core I2C designware driver still accesses the fields in the driver
struct that we no longer populate, and proceeds to calculate them from
the clock frequency. Since the clock frequency is unspecified, the
driver complains loudly using a WARN_ON().
So revert back to the old situation, where the struct fields for all
timings are populated, but retain the new logic which chooses the SDA
hold time from the timing mode that is currently in use.
Fixes: bd698d24b1b57 ("i2c: designware: Get selected speed mode ...")
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
drivers/i2c/busses/i2c-designware-platdrv.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)
Thanks, this is ok to me. Let's add also kudos to Lorenzo:
Reported-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Acked-by: Jarkko Nikula <jarkko.nikula@xxxxxxxxxxxxxxx>
Thanks. I suppose this is going in as a fix? If not, please cc to -stable
That's not needed as the bd698d24b1b57 came during pre 4.12-rc1 cycle.
But good to get this into 4.12 due probable regression in high-speed
transfers and to get rid of log spamming.
--
Jarkko
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