Subject: Re: umass problems with camera
To: Lennart Augustsson <>
From: Gary Duzan <>
List: current-users
Date: 01/03/2004 04:35:54
In Message <> , (Lennart Augustsson) wrote:

=>Steven M. Bellovin wrote:
=>> Is this the cause of USB mass storage devices silently doing nothing 
=>> useful when they're plugged in?  I'm glad it's been found, and a 
=>> message is better than nothing, but is a better fix possible?  In 
=>> particular, is there some way that that some amount of space can be 
=>> reserved at boot time for later use by USB storage devices?
=>It could be fixed properly in the USB code, but that's more work
=>than I have time for at the moment.
=>All it's trying to allocate is 64K of contiguous memory.  That didn't
=>seem to be a problem in the olden days.  I'm not sure when it changed.
=>Maybe with UVM or UBC.

   FWIW, I had this 'no buffer memory' problem recently with a
Memorex ThumbDrive, and managed to get around it by checking
vm.nkmempages, adding 128 or so to its value (probably overkill,
but it worked), and adding the NKMEMPAGES_MIN option to the kernel:

options 	NKMEMPAGES_MIN=32868

umass0 at uhub1 port 2 configuration 1 interface 0
umass0: USB Solid state disk, rev 1.10/1.00, addr 3
umass0: using SCSI over Bulk-Only
scsibus0 at umass0: 2 targets, 1 lun per target
sd0 at scsibus0 target 0 lun 0: <Memorex, ThumbDrive, 1.12> disk removable
sd0: fabricating a geometry
sd0: 64512 KB, 63 cyl, 64 head, 32 sec, 512 bytes/sect x 129024 sectors

					Gary Duzan