Re: Hot-plugging microSD on Raspberry Pi under FreeBSD
Date: Mon, 27 Dec 2021 00:40:23 UTC
On 2021-Dec-26, at 14:47, bob prohaska <fbsd@www.zefox.net> wrote: > On Sun, Dec 26, 2021 at 01:00:38PM -0800, Mark Millard via freebsd-arm wrote: >> On 2021-Dec-26, at 11:23, bob prohaska <fbsd@www.zefox.net> wrote: >> >>> >>> Obviously filesystems have to be gracefully unmounted, but is >>> that all? Can the kernel be "aware" of an unused device and >>> get confused if it goes away? >> >> As I remember, for FreeBSD, >> >> A) The built-in microsd card slot works fine for swapping >> media that are not mounted at the time. > > Ok, that's reassuring. I observed corruption of microSD card FAT > partitionss and wondered if hot-plugging might be the cause. I could do a similar check of this context later. >> >> but, for example (no mounts involved, RPi4B 8GiByte test context), >> >> B.0) Plug-in the USB reader, no media present. (USB3 example here.) >> B.1) Insert a 128 GiByte media to the reader. >> B.2) Remove that media. >> B.3) Insert a 32 GiByte media to the reader >> (same slot in the reader). >> >> Result: >> >> (da4:umass-sim1:1:0:3): READ(10). CDB: 28 00 0e e2 af ff 00 00 01 00 > > [...disk errors snipped....] > > Was the Pi4 running from a USB hard disk? USB3 SSD. I do not have the marginal/insufficient power issues that you have. > I ask because plugging in a USB reader to my RasPiOS Pi4 while booted > from a USB hard disk seems to disrupt communication with the boot drive. You have described having a marginal/insufficient power context in other messages. > It doesn't crash immediately but can't be gracefully rebooted. > >> If you do the 32 GiByte first instead, then for the 128 GiByte you >> get notices from GEOM_PART about "was automatically resized" >> but it does not "address out of range". > > That seems like the "confusion" I was wondering about. The kernel > notices the first card insertion, fails to notice the removal and > then mis-attributes the change to a partition resize. I disconnect the reader, swap media, and reconnect. That handles things fine. >> I expect that swapping two media of the same capacity would >> be less likely to generate any messages, but that does not >> mean that such a swap would be handled fully correctly. >> >> So I unplug the whole reader to swap media. This is messier >> if multiple slots are in use (more unmounts and later >> remounts). > > That chain of events crashes my RasPiOS Pi4, at least when it's also > booted from a USB drive. > You have described having a marginal/insufficient power context in other messages. === Mark Millard marklmi at yahoo.com