Firmware debugging patches?
egrumbach at gmail.com
Mon Jun 2 11:46:36 PDT 2014
> [Good stuff snipped, adding linux-wireless as this is a more
> general issue if we are going to consider general framework]
> Maybe we should start with goals before getting to implementation
> details. Here's my wish list that is ath10k specific, but probably
> similar to other firmware users:
> 1) We need the firmware crash text currently printed to
> 2) It would be nice to get the firmware RAM and stack dumps at time of
> crash to debug more interesting crashes.
Right - but typically you'll have closed source / IP / whatever there..
> 3) It would be nice to know about firmware debug messages for
> the period of time directly before the crash (maybe 2-5 minutes?)
> 4) It would be nice to have this interleaved with kernel, supplicant,
> and related logs.
> We need a solution for different types of users. I suspect the number
> of crashes seen in the wild will be more for users nearer the top
> of this list.
> a) Normal Fedora/Ubuntu/etc default-installed distribution user
> with ath10k NIC has wifi issues, firmware crashes, they don't
> really know what firmware means or that it crashed, but some automated crash-log
> tool notices and gathers debug info for automated bug reporting.
I am working on that for our firmware. I recently added such capability relying on udev to notify the userspace that something bad happens. I gather all the data and prepare a binary file that is sent through debugfs (pulled by a script triggered by udev). I remember the first crash only.
> b) Slightly more advanced user actually notices the problem at coffee shop
> earlier today, posts about it when they get home, and we ask for
> debug info.
> c) Experienced and determined user has similar issues, but is able to
> reproduce the problem and/or turn on more advanced debugging efforts.
> d) Even more determined user that can and will recompile kernels and/or
> try patches.
> Anything that has to be enabled before-hand will not help a) and b) above.
> If support is not compiled into default kernels, c) will not help you either.
> If it is difficult or requires acquiring cutting edge tools not in their
> distribution by default, many of c) and some of d) will just ignore the problem or use
> different hardware.
> If we are storing crashes for something like ethtool to report, we need
> RAM and/or disk storage so the firmware RAM dumps and such can be stored until
> the user and/or automated tools ask for them. We need some way to automatically
> clean up old crashes so disk/ram is not overly utilized. For APs,
> they are low on both RAM and 'disk', so storing crash logs for any
> length of time may be problematic.
I did something simpler - but it works. I don't really know the ethtool infrastructure though.
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