Re: kern/55512: sdmmc locking broken

[mlelstv%serpens.de@localhost (Michael van Elst)]

The following reply was made to PR kern/55512; it has been noted by GNATS.

From: mlelstv%serpens.de@localhost (Michael van Elst)
To: gnats-bugs%netbsd.org@localhost
Cc: 
Subject: Re: kern/55512: sdmmc locking broken
Date: Wed, 22 Jul 2020 15:19:18 -0000 (UTC)

 martin%duskware.de@localhost (Martin Husemann) writes:
 
 > That would be fine, but still the locking seems to be broken. I'm
 > pretty sure I saw concurrent cmds issued by different CPUs while trying
 > to debug my eMMC issue (the strange timings you noticed in my debug
 > lock on tech-kern) on Odroid C2.
 
 Actually I noticed that the driver returned a timeout while almost
 no time had passed, definitely not qualifying for a timeout.
 
 kprintf uses getnanouptime(), I'm not sure if readouts on
 different CPUs are guaranteed to be monotonic.
 
 -- 
 -- 
                                 Michael van Elst
 Internet: mlelstv%serpens.de@localhost
                                 "A potential Snark may lurk in every tree."