On Thu, 22 Jul 2010, Andy Shevchenko wrote: > MS Windows mounts removable storage in "Removal optimized mode" by > default. All the writes to the media are synchronous which is achieved > by setting FUA (Force Unit Access) bit in SCSI WRITE(10,12) commands. > This prevents I/O requests aggregation in block layer dramatically > decreasing performance. > > This patch brings an option to accept or ignore mentioned bit > a) via specifying module parameter "nofua", or > b) through sysfs entry > /sys/devices/platform/musb_hdrc/gadget/gadget-lun-X/nofua > > Patch is based on the work that was done by Denis Karpov for Maemo 5 > platform. > > Signed-off-by: Andy Shevchenko <ext-andriy.shevchenko@xxxxxxxxx> > Cc: Denis Karpov <ext-denis.2.karpov@xxxxxxxxx> > Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx> > Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> > Cc: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx> > Cc: Greg Kroah-Hartman <gregkh@xxxxxxx> > Cc: linux-usb@xxxxxxxxxxxxxxx > --- > .../sysfs-devices-platform-musb_hdrc-gadget | 12 +++++++ > drivers/usb/gadget/file_storage.c | 31 +++++++++++++++---- > drivers/usb/gadget/storage_common.c | 28 ++++++++++++++++++ > 3 files changed, 64 insertions(+), 7 deletions(-) > create mode 100644 Documentation/ABI/testing/sysfs-devices-platform-musb_hdrc-gadget > > diff --git a/Documentation/ABI/testing/sysfs-devices-platform-musb_hdrc-gadget b/Documentation/ABI/testing/sysfs-devices-platform-musb_hdrc-gadget > new file mode 100644 > index 0000000..192d3f3 > --- /dev/null > +++ b/Documentation/ABI/testing/sysfs-devices-platform-musb_hdrc-gadget > @@ -0,0 +1,12 @@ > +What: /sys/devices/platform/musb_hdrc/gadget/gadget-lun-X/nofua The name of the new file and the path given here shouldn't mention musb_hdrc. That's what _you_ see because that's the device controller driver you use, but other people will see something different. As a simple test, you might try using dummy_hcd instead and see what the name turns out to be. Just put "..." instead of "musb_hdrc", or something like that. > +Date: July 2010 > +Contact: Andy Shevchenko <andy.shevchenko@xxxxxxxxx> > +Description: > + Show or set the reaction on the FUA (Force Unit Access) bit in > + the SCSI WRITE(10,12) commands when a gadget in USB Mass > + Storage mode. > + > + Possible values are: > + 1 -> ignore FUA flag > + 0 -> follow on it Change this to "obey the FUA flag". The rest is okay. Subject to these changes: Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> -- 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
