re: port-arm/55922: Kernel panics with nvme+gpt on Pinebook Pro

[matthew green <mrg%eterna.com.au@localhost>]

The following reply was made to PR port-arm/55922; it has been noted by GNATS.

From: matthew green <mrg%eterna.com.au@localhost>
To: Nick Hudson <nick.hudson%gmx.co.uk@localhost>, bsiegert%gmail.com@localhost
Cc: gnats-bugs%netbsd.org@localhost, port-arm-maintainer%netbsd.org@localhost,
    gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost
Subject: re: port-arm/55922: Kernel panics with nvme+gpt on Pinebook Pro
Date: Tue, 07 Sep 2021 05:58:22 +1000

 what's the nvme ssd installed?  there are known issues with
 many mid-range to high-end ssds in pbp, due to power supply
 issues.  see this for info about known good bad:
 
    https://wiki.pine64.org/wiki/Pinebook_Pro_Hardware_Accessory_Compatibil=
 ity#NVMe_SSD_drives
 
 but also know that all the samsung drives *i* tried did not
 work in the end (this table lists 970 PRO as working, and
 maybe it does work at PS2 setting.)
 
 you can (should) set the nvme power level to PS2 if you can,
 using nvmectl:
 
    nvmectl power -p 2 nvme0
 
 
 now that i've become more familiar with this failure mode,
 i'm some what convinced this PR is a hardware issue and
 we can't solve it in software.  the mutex spinout happened
 because the hardware stopped answering.
 
 
 it's also possible that even with nvme set to ~2W that
 also having the system run -j6 for a long time -- which
 does drain the battery normally -- will lead to a case
 where the battery can't supply power to the nvme and it
 can fail, even with "good low power" nvmes.  i have intel
 660p's in use, and while mostly it can run down on power
 OK, sometimes it will hang IOs and need a reset.
 
 
 .mrg.