On Tue, 16 Jun 2015, Xuebing Wang wrote: > Hi Alan and community, > > I am using mass storage kernel module of v4.0.1 for Freescale i.MX6SL > for a commercial product. As this is commercial product, thus USB host > compatibility is important. > > 1) It seems that Windows 7 host can *not* auto-mount if I pass > parameters as below: > modprobe g_mass_storage file=/dev/mmcblk0p4 iSerialNumber=abcdefgh nofua=1 Have you read this sentence from the USB Mass Storage Class Bulk-Only Transport specification (section 4.1.1 Serial Number)? The serial number shall contain at least 12 valid digits, represented as a UNICODE string. I don't know if Windows pays any attention to the length of the serial number string, but it might. Also, take a look at section 4.1.2 Valid Serial Number characters: It lists '0' - '9' and 'A' - 'F' but not 'a' and certainly not 'g' or 'h'. > 2) Windows 7 can auto-mount, if I pass pass parameters as below (with > removable=1) > modprobe g_mass_storage file=/dev/mmcblk0p4 iSerialNumber=abcdefgh > nofua=1 removable=1 > > But, there is a problem. If I eject the removable disk from Win7, > disconnect USB cable, and re-connect the USB cable, the removable disk > can NOT be auto-mounted on Win7. Well, sure. The same thing happens with real USB storage devices. For example, if you eject a CDROM from a USB CD player, the removable CD can't be auto-mounted until you put a CDROM back into the player. Unplugging and re-connecting the USB cable won't help. > It seems this makes sense, because Documentation/usb/mass-storage.txt > says below: > ------ > If this option (removable=1) is set for a logical unit, gadget will > accept an > “eject” SCSI request (Start/Stop Unit). When it is sent, the > backing file will be closed to simulate ejection and the logical > unit will not be mountable by the host until a new backing file is > specified by userspace on the device (see “sysfs entries” > section). > ------ > > Would you please advise what is the best way to pass parameters to > g_mass_storage considering host compatibility? This has nothing to do with parameters. If you want the storage to be auto-mounted, don't eject it! Use the "Safely remove hardware" button in Windows instead. Also, what happens if you specify a _valid_ serial number and leave out the "removable=1" parameter? Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
