Date: Thu, 06 Sep 2012 15:18:18 +0200 From: "Stanislaw W." <erikses@gmail.com> To: freebsd-usb@freebsd.org Subject: Re: how to force my 32G usb pendrive to flush write cache in RAM it has? Message-ID: <5048A29A.80305@gmail.com> In-Reply-To: <20120906014753.2aaa126f@asd.localdomain> References: <20120904235557.7ca40fc8@epc.localdomain> <20120906014753.2aaa126f@asd.localdomain>
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W dniu 05.09.2012 23:47, Anatoly pisze: > В Tue, 4 Sep 2012 23:55:57 +0400 > Anatoly <> пишет: > >> Hello, >> I have a problem with my new 32G pendrive: >> >> da1: <JetFlash Transcend 32GB 8.07> Removable Direct Access SCSI-2 >> device da1: 40.000MB/s transfers >> da1: 30640MB (62750720 512 byte sectors: 255H 63S/T 3906C) >> >> I'm using fat32 partition on it. >> To make problem occur I can do following things: >> 1) write a file about 5MB in size on that partition >> 2) unmount >> 3) unplug pendrive (so it loses power) >> 4) plug it again >> 5) mount >> Now I can see that the end of file is corrupted. >> >> Poblem never occurs when I do: >> 1) write a file about 5MB in size on that partition >> 2) unmount >> 3) mount >> Also, problem doesn't occur if I'll wait for more than ~10 minutes >> before unplugging pendrive. >> >> So it seems to me that this pendrive has internal write cache in RAM >> that needs to be flushed before pendrive loses power. >> Problem never occurs with Windows. As I click "remove", windows >> somehow "correctly shutdowns" pendrive so it's LED goes off (Unlike >> if i just unmount, when the LED stays on) >> >> What can I do to get cache flushed before unpugging, turn that write >> cache off, or any other suggestions? >> I've tried camcontrol stop and camcontrol eject with no >> success >> I using FreeBSD 7.3 with generic kernel here > I've found solution: > http://lists.freebsd.org/pipermail/freebsd-usb/2008-March/004677.html > that 'upower' utility allows to suspend pendrive, and I get cache > flushed (And LED goes off): > upower /dev/usb0 2 suspend > _______________________________________________ > freebsd-usb@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-usb > To unsubscribe, send any mail to "freebsd-usb-unsubscribe@freebsd.org" > To flush cache You can also use sync(8) Stanislaw.
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