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    SubjectRe: 2.6.24-rc5-mm1
    On Dec 14, 2007 11:44 PM, Alan Stern <stern@rowland.harvard.edu> wrote:
    > On Fri, 14 Dec 2007, Dave Young wrote:
    >
    > > Hi,
    > > The behaviour of my mp3 player (also act as usb-storage device) seems
    > > changed from rc5 to rc5-mm1.
    >
    > This can't be considered a bug, right?

    I'm not sure.

    > It's just that the player
    > changed from one slightly non-standard behavior to a different slightly
    > non-standard behavior.
    >
    >
    > > <dmesg output under rc5>:
    > > =========
    > > usb 1-7: new high speed USB device using ehci_hcd and address 7
    > > usb 1-7: configuration #1 chosen from 1 choice
    > > scsi4 : SCSI emulation for USB Mass Storage devices
    > > usb-storage: device found at 7
    > > usb-storage: waiting for device to settle before scanning
    > > scsi 4:0:0:0: Direct-Access Newman mp3 PQ: 0 ANSI: 0 CCS
    > > sd 4:0:0:0: [sdb] 245248 512-byte hardware sectors (126 MB)
    > > sd 4:0:0:0: [sdb] Write Protect is on
    > > sd 4:0:0:0: [sdb] Mode Sense: 03 00 80 00
    > > sd 4:0:0:0: [sdb] Assuming drive cache: write through
    > > sd 4:0:0:0: [sdb] 245248 512-byte hardware sectors (126 MB)
    > > sd 4:0:0:0: [sdb] Write Protect is on
    > > sd 4:0:0:0: [sdb] Mode Sense: 03 00 80 00
    > > sd 4:0:0:0: [sdb] Assuming drive cache: write through
    > > sdb: sdb1
    > > sd 4:0:0:0: [sdb] Attached SCSI removable disk
    > > sd 4:0:0:0: Attached scsi generic sg1 type 0
    > > usb-storage: device scan complete
    > >
    > > ==========
    > > try mount it (or just blockdev --rereadpt), then write protect become off:
    > > ==========
    > >
    > > sd 4:0:0:0: [sdb] 245248 512-byte hardware sectors (126 MB)
    > > sd 4:0:0:0: [sdb] Write Protect is off
    > > sd 4:0:0:0: [sdb] Mode Sense: 03 00 00 00
    > > sd 4:0:0:0: [sdb] Assuming drive cache: write through
    > > sd 4:0:0:0: [sdb] 245248 512-byte hardware sectors (126 MB)
    > > sd 4:0:0:0: [sdb] Write Protect is off
    > > sd 4:0:0:0: [sdb] Mode Sense: 03 00 00 00
    > > sd 4:0:0:0: [sdb] Assuming drive cache: write through
    > > sdb: sdb1
    >
    > This output won't appear if you simply mount the device. So how do you
    > know that mounting turns off write protect?

    This can be observed by eye:
    dmesg -> mount -> dmesg

    >
    > > But under rc5-mm1, after mount command being executed, it is just
    > > mouted as read only partition without set the write-protect to off
    > >
    > > I tried "blockdev --rereadpt", it do set the write-protect to off as rc5 kernel.
    > >
    > > Below is the output of dmesg under rc5-mm1
    > > ==========
    > > usb 1-8: new high speed USB device using ehci_hcd and address 6
    > > usb 1-8: configuration #1 chosen from 1 choice
    > > scsi3 : SCSI emulation for USB Mass Storage devices
    > > usb-storage: device found at 6
    > > usb-storage: waiting for device to settle before scanning
    > > scsi 3:0:0:0: Direct-Access Newman mp3 PQ: 0 ANSI: 0 CCS
    > > sd 3:0:0:0: [sdb] 245248 512-byte hardware sectors (126 MB)
    > > sd 3:0:0:0: [sdb] Write Protect is on
    > > sd 3:0:0:0: [sdb] Mode Sense: 03 00 80 00
    > > sd 3:0:0:0: [sdb] Assuming drive cache: write through
    > > sd 3:0:0:0: [sdb] 245248 512-byte hardware sectors (126 MB)
    > > sd 3:0:0:0: [sdb] Write Protect is on
    > > sd 3:0:0:0: [sdb] Mode Sense: 03 00 80 00
    > > sd 3:0:0:0: [sdb] Assuming drive cache: write through
    > > sdb: sdb1
    >
    > This looks exactly the same as the output above (except for various
    > port, device, and bus numbers).

    Yes, but lacks the part of "'Write Protect if off' and other lines".

    >
    > If you turn on CONFIG_USB_STORAGE_DEBUG for both kernels and compare
    > the dmesg output for the mount command, that might highlight the
    > difference.

    Ok, I will test with do once have time, thanks.

    Regards
    dave


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