Date: Sun, 26 Dec 2021 16:40:23 -0800 From: Mark Millard via freebsd-arm <freebsd-arm@freebsd.org> To: bob prohaska <fbsd@www.zefox.net> Cc: freebsd-arm@freebsd.org Subject: Re: Hot-plugging microSD on Raspberry Pi under FreeBSD Message-ID: <1D17056C-AA76-4CF8-8A2C-C2908242AAFE@yahoo.com> In-Reply-To: <20211226224709.GB16188@www.zefox.net> References: <20211226192338.GA16188@www.zefox.net> <91D4CF6B-5690-413D-A873-2DB50CAF9637@yahoo.com> <20211226224709.GB16188@www.zefox.net>
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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: >>=20 >>>=20 >>> 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? >>=20 >> As I remember, for FreeBSD, >>=20 >> A) The built-in microsd card slot works fine for swapping >> media that are not mounted at the time. >=20 > Ok, that's reassuring. I observed corruption of microSD card FAT=20 > partitionss and wondered if hot-plugging might be the cause. I could do a similar check of this context later. >>=20 >> but, for example (no mounts involved, RPi4B 8GiByte test context), >>=20 >> 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). >>=20 >> Result: >>=20 >> (da4:umass-sim1:1:0:3): READ(10). CDB: 28 00 0e e2 af ff 00 00 01 00=20= >=20 > [...disk errors snipped....] >=20 > 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=20= > from a USB hard disk seems to disrupt communication with the boot = drive.=20 You have described having a marginal/insufficient power context in other messages. > It doesn't crash immediately but can't be gracefully rebooted. >=20 >> 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". >=20 > 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. >>=20 >> So I unplug the whole reader to swap media. This is messier >> if multiple slots are in use (more unmounts and later >> remounts). >=20 > That chain of events crashes my RasPiOS Pi4, at least when it's also > booted from a USB drive.=20 >=20 You have described having a marginal/insufficient power context in other messages. =3D=3D=3D Mark Millard marklmi at yahoo.com
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