-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 John Crispin <blo...@openwrt.org> wrote: > > > On 19/02/2016 18:00, Karl Palsson wrote: > > Hi, > > > > I'm trying to get "block mount" to behave well when a microSD > > card is removed/inserted from a fixed USB card reader. I've > > compiled the uevent-hotplug debugger example from > > https://www.kernel.org/doc/pending/hotplug.txt and running that > > on my device, I can see that "block info" is somehow triggering > > the uevent change notifications I hope. (I can't see anywhere in > > the fstools how the uevent is triggered, but it only happens if I > > run "block info" manually, "blkid" doesn't trigger any events, so > > it's something in block info > > > > Example event (unfortuntely it's identical for card inserted -> > > removed and for removed -> inserted) > > ``` > > change@/devices/platform/ehci-platform/usb1/1-1/1-1.1/1-1.1:1.0/host0/target0:0:0/0:0:0:0/block/sda > > ACTION=change > > DEVPATH=/devices/platform/ehci-platform/usb1/1-1/1-1.1/1-1.1:1.0/host0/target0:0:0/0:0:0:0/block/sda > > SUBSYSTEM=block DISK_MEDIA_CHANGE=1 MAJOR=8 MINOR=0 DEVNAME=sda > > DEVTYPE=disk SEQNUM=637 > > ``` > > > > > fstools/libblkid-tiny/libblkid-tiny.c: probe_block() > > does an open() on the device node which will eventually end up > inside > > drivers/scsi/sd.c: sd_open() > > which will call check_disk_change(bdev); > > and that triggers the uevent.
Ahh, thanks. > > i am not sure how you can get it to automatically send the > event without polling it. I can live with that, my real concern is that I want it to be unmounted/mounted. Should "block hotplug" be handling this to add/remove? I can work on adding this to handle the change events, but is that the right way, and would that be accepted, or should something else be converting them into add/remove events elsewhere? On desktop linux, I see the change event with DISK_MEDIA_CHANGE=1, then a subsequent add/remove event. As for automatically getting the event, I can enable the kernel event polling, by setting /sys/block/sda/events_poll_msecs to ~500ms or so, and I can then see the SCSI LUN check commands with usbmon, and I can see the responses change as soon as the card is inserted/removed, but no events come out. I kinda feel that's something I should take up upstream, but I'm perfectly ok with having to poll "block info" at the moment. Sincerely, Karl P -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQIcBAEBAgAGBQJWyMezAAoJEBmotQ/U1cr2xQsP/2nC9BiSIcMwR/2QZg4QvvyR 65+uZ7cRoGutmPd2V7QQu/ZAtwET9lft8CgYh5uY1htNEvVTjEagz1+1yAjrqAau Uc4uEOmwteXupIIAQeB/nTheAugfvt8+PhzXAAxyHxtV4udyYdM0wp8sDFvw201/ R2n9fgDyz8Oyw+qtf3vNPZcHXHGb7ewM8GTxkjnkeKMTCt307hDjh3uAVBNQvdem 3sQpx13nMgfbT6jVlXya8QMvOozW5P/1w9cOJUPDlAgdeZd3H6WbZ9YI1mivJgUa F/LTfmheHqwXPj6HTVZ7nuHe10SqXRjrDike88FxjOtyp/gg7tleuWNSzZ8Rq8gj 40JHU9HdUJ5CWKMGjnI10gbj/zW9s+9OiLRWHUHW242WLIe3lTckosyPLoKi2VtB svqqv3aNnHM0Esf1EKDVFiu0KqP0cZWaE+UOGRm+kp/+4pp35l5mOtzonZtbLWF5 FOR4y/fJmJmpwi9MrNo6e1fPxpr+IxSv6bmNvH2mEvbX9DspH3a8tJX6AsQsVweJ s6D1N+QQnHNEnIF2gXvGwLAGvItlifJM3p+4v9dUBb5XQtHxzraVkW7ygx5XfOhn MWc9MxDwlEYJd0DIPWAQ8ORrEfkJ+49oklnGWjxAe48K/A5jx2zs/Ve7YMpATMp7 nDRP9DPTizzcQcHH3gA8 =Hdwm -----END PGP SIGNATURE-----
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