On 08/30/2017 04:23 AM, Phil Reid wrote:
On 30/08/2017 05:00, Wolfram Sang wrote:
I don't know enough about real-world ACPI tables to suggest a best
practice here. I just wanted to add that busses < 100 kHz are legal from
how I read the specs.
Oh well, Jarkko liked the patch, so let's all sleep over this patch and
if nothing else comes up, I'll apply it tomorrow or so...
My understanding is 100k is what the client must support.
But sometimes buses need to be run slower.
Particularly when using range extenders.
eg: I have an i2c bus running over a 10m cable that needs to run at
about 40k
to be reliable.
I acked the patch because I see it as a possibility for a regression if
we blindly accept slower than 100 kHz speed from ACPI without validating
does that result working setup and timing parameters.
It is better to have an another patch explicitly adding support for
< 100 kHz speeds when needed.
--
Jarkko
