On Tue, 10 Oct 2023 16:00:13 -0700 Paul M Stillwell Jr wrote:

quoted

quoted

+Retrieving FW log data
+~~~~~~~~~~~~~~~~~~~~~~
+The FW log data can be retrieved by reading from 'fwlog/data'. The user can
+write to 'fwlog/data' to clear the data. The data can only be cleared when FW
+logging is disabled.  

Oh, now it sounds like only one thing can be enabled at a time.
Can you clarify?
  

What I'm trying to describe here is a mechanism to read all the data 
(whatever modules have been enabled) as it's coming in and to also be 
able to clear the data in case the user wants to start fresh (by writing 
0 to the file). Does that make sense?

Yes that part does.

I probably wasn't clear in the 
previous section that the user can enable many modules at the same time.

Probably best if you describe enabling of multiple modules in the
example. I'm not sure how one disables a module with the current API.

quoted

Why 4K? The number of buffers is irrelevant to the user, why not let
the user configure the size in bytes (which his how much DRAM the
driver will hold hostage)?  

I'm trying to keep the numbers small for the user :). I could say 
1048576 bytes (256 x 4096), but those kinds of numbers get unwieldy to a 
user (IMO).

echo $((256 * 4096)) >> $the_file

But also...

The FW logs generate a LOT of data depending on what modules are enabled 
so we typically need a lot of buffers to handle them.

In the past we have tried to use the syslog mechanism, but we generate 
SO much data that we overwhelm that and lose data. That's why the idea 
of using static buffers is appealing to us. We could still overrun the 
buffers, but at least we will have contiguous data. The problem then 
becomes one of allocating enough space for what the user is trying to 
catch instead of trying to start/stop logging and hoping you get all the 
events in the log.

I can drop the mention of 4K buffers in the documentation. Or we could 
use terms like 1M, 2M, 512K, et al. That would require string parsing in 
the driver though and I'm trying to avoid that if possible. What do you 
think?

.. I thought such helpers already existed.