Thread (30 messages) 30 messages, 4 authors, 2021-03-18

Re: Errant readings on LM81 with T2080 SoC

From: Chris Packham <Chris.Packham@alliedtelesis.co.nz>
Date: 2021-03-10 02:20:49
Also in: linux-hwmon, linux-i2c, lkml

On 9/03/21 9:27 am, Chris Packham wrote:
On 8/03/21 5:59 pm, Guenter Roeck wrote:
quoted
Other than that, the only other real idea I have would be to monitor
the i2c bus.
I am in the fortunate position of being able to go into the office and 
even happen to have the expensive scope at the moment. Now I just need 
to find a tame HW engineer so I don't burn myself trying to attach the 
probes.
One thing I see on the scope is that when there is a CPU load there 
appears to be some clock stretching going on (SCL is held low some 
times). I don't see it without the CPU load. It's hard to correlate a 
clock stretching event with a bad read or error but it is one area where 
the SMBUS spec has a maximum that might cause the device to give up waiting.
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