Date: Thu, 23 Dec 2010 14:47:32 +0100 (CET) From: Oliver Fromme <olli@lurza.secnetix.de> To: lev@serebryakov.spb.ru (Lev Serebryakov) Cc: freebsd-geom@FreeBSD.ORG Subject: Re: FreeBSD 8.2-PRERELASE doesn't see slice on SDHC card in ?cardreader ?-- what should I do? Message-ID: <201012231347.oBNDlW63033296@lurza.secnetix.de> In-Reply-To: <141767543.20101223161430@serebryakov.spb.ru>
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Lev Serebryakov wrote: > Oliver Fromme wrote: > > Lev Serebryakov <lev@serebryakov.spb.ru> wrote: > > > It works! But it is not intiutive at all :) > > > > The command opens the device for writing (but it doesn't > > actually write anything), and closes it immediately. > > This causes the GEOM system to read and "taste" the > > device and look for new slices or partitions. > > I understand, what these command do, but geom retaste is not obvious > result and it is not obvious, that it is proper (and easiest) way to > trigger re-taste. Right, it is not obvious, and it's not really "proper". It's rather a bad hack. But it's currently the only work- around that exists, AFAIK. Of course, I *do* agree that there should be a better way to do it. > > > Why all CAM-related commands like "load" and "open" don't work > > > > All of those commands are only related to the hardware, > > i.e. SCSI busses and devices. They are not related to > > the _content_ of the device (slices etc.). > > Yes, but each device is geom_disk, and re-scanning hardware level > could trigger re-taste, starting from releant geom_disks. It looks > resonable. The problem is that nothing has changed, from the hardware point of view. The SCSI re-scan did not encounter any new devices or anything else, so there doesn't _seem_ to be a reason to re-taste everything. > > > (I don't mention auto-sensing ;-))? Is it problem with my > > > cardreader or common problem for FreeBSD? > > > > The main problem here is that there is no notification > > mechanism when you insert an SD card (the same is true > > for floppy disks and CD drives, by the way, but it's less > > of a problem because they usually don't have slices). > > It is strange. Any SD card reader has spring contacts, which > detects card insertion. Does cardreader pass this signal? No. As far as I know, USB mass storage devices cannot send anything on their own. They can only send replies when being asked by the USB host. So the host would have to poll for a change in regular intervals, which is not really optimal either. > And I'm sure, that SCSI (and ATAPI, as ATAPI is SCSI-commands- > over-ATA) CD-ROM drives has "media changed" signal. Yes, but only if you actively poll for it (which can have undesirable side effects, like drive LED flashing, or clicking sounds from the drive's motor). There is no notification like an interrupt signal or something like that. Best regards Oliver -- Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing b. M. Handelsregister: Registergericht Muenchen, HRA 74606, Geschäftsfuehrung: secnetix Verwaltungsgesellsch. mbH, Handelsregister: Registergericht Mün- chen, HRB 125758, Geschäftsführer: Maik Bachmann, Olaf Erb, Ralf Gebhart FreeBSD-Dienstleistungen, -Produkte und mehr: http://www.secnetix.de/bsd "The ITU has offered the IETF formal alignment with its corresponding technology, Penguins, but that won't fly." -- RFC 2549
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