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On Wed, Oct 12, 2011 at 12:40:23AM -0400, Walter Dnes wrote: |
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> Hi all |
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> |
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> Recently, there was a firestorm on the gentoo-user list over the idea |
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> that udev would eventually require /usr to be on the same physical |
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> parition as /, or else use initramfs, which is its own can of worms. I'm |
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> not a programmer, let alone a developer. Rather than merely ranting, I |
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> went and searched for an alternative. |
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... |
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> |
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> Another option is to take the current Gentoo setup, drop udev and |
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> use mdev in the same manner as Alpine uses it. In case anyone asks, |
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> auto mounting should still be possible. Attached is an excerpt from |
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> /var/log/messages from a basic Alpine install. The kernel messages were |
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> generated when I inserted a USB key into a usb jack. |
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|
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Seeing from the prior conversations here (sorry for lack of citation) |
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and |
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http://lists.busybox.net/pipermail/busybox/2011-September/076710.html |
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, I suspect that the root problem isn't with udev itself but with the |
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udev rules. |
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|
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The magic which makes automatic userspace configuration possible is in |
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the udev rules and makes udev appear to be the problem. For example, |
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if you switch to mdev currently, you will notice that X11's device |
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autodetection doesn't work so well. (At least for me, X11's |
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autodetection magically works for detecting input devices with udev |
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but not with mdev). It is concievable that you could develop a |
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parallel database of mdev-compatible rules and even let packages |
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install rules specific to themselves (with modification to mdev |
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http://lists.busybox.net/pipermail/busybox/2011-September/076666.html |
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). With these sorts of things, you might figure out a way to make |
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X11's device autoconfiguration work or perform other device |
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initialization tasks. But at the same time, you have a good chance of |
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accidentally introducing a reliance on libraries/programs installed to |
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/usr. This latter problem is the issue, deciding how much software |
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should have --prefix=/ versus the normal --prefix=/usr. |
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|
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You can already try out what using mdev instead of udev is like in |
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Gentoo. Just add `sys-apps/busybox mdev' to /etc/portage/package.use, |
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remerge busybox. You must be sure to be using busybox-1.92.2 or later |
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for bug #83301. |
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|
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# rc-update add mdev sysinit |
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# rc-update del udev sysinit |
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|
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But be 'ware that this isn't guaranteed to provide a successful boot |
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;-). |
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|
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> Oct 9 13:46:00 e521 kern.info kernel: [10714.105621] usb 2-8: new high speed USB device using ehci_hcd and address 4 |
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> Oct 9 13:46:00 e521 kern.info kernel: [10714.241353] usb 2-8: New USB device found, idVendor=13fe, idProduct=1e00 |
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> Oct 9 13:46:00 e521 kern.info kernel: [10714.241357] usb 2-8: New USB device strings: Mfr=1, Product=2, SerialNumber=3 |
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> Oct 9 13:46:00 e521 kern.info kernel: [10714.241360] usb 2-8: Product: Patriot Memory |
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> Oct 9 13:46:00 e521 kern.info kernel: [10714.241362] usb 2-8: Manufacturer: |
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> Oct 9 13:46:00 e521 kern.info kernel: [10714.241364] usb 2-8: SerialNumber: 078215A302CF |
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> Oct 9 13:46:00 e521 kern.info kernel: [10714.244241] scsi4 : usb-storage 2-8:1.0 |
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> Oct 9 13:46:01 e521 kern.notice kernel: [10715.279753] scsi 4:0:0:0: Direct-Access Patriot Memory PMAP PQ: 0 ANSI: 0 CCS |
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> Oct 9 13:46:02 e521 kern.notice kernel: [10715.930991] sd 4:0:0:0: [sdb] 31326208 512-byte logical blocks: (16.0 GB/14.9 GiB) |
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> Oct 9 13:46:02 e521 kern.notice kernel: [10715.931980] sd 4:0:0:0: [sdb] Write Protect is off |
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> Oct 9 13:46:02 e521 kern.debug kernel: [10715.931983] sd 4:0:0:0: [sdb] Mode Sense: 23 00 00 00 |
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> Oct 9 13:46:02 e521 kern.err kernel: [10715.931986] sd 4:0:0:0: [sdb] Assuming drive cache: write through |
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> Oct 9 13:46:02 e521 kern.err kernel: [10715.935986] sd 4:0:0:0: [sdb] Assuming drive cache: write through |
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> Oct 9 13:46:02 e521 kern.info kernel: [10715.981381] sdb: sdb1 |
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> Oct 9 13:46:02 e521 kern.err kernel: [10715.986028] sd 4:0:0:0: [sdb] Assuming drive cache: write through |
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> Oct 9 13:46:02 e521 kern.notice kernel: [10715.986035] sd 4:0:0:0: [sdb] Attached SCSI removable disk |
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|
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Unless if I'm missing something, those messages _always_ show up even |
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if udev or mdev haven't been invoked. |
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|
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-- |
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binki |
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|
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Look out for missing or extraneous apostrophes! |