On Thu, Apr 30, 2015 at 12:37:15AM -0500, Felipe Balbi wrote: > On Thu, Apr 30, 2015 at 10:46:51AM +0800, Xuebing Wang wrote: > > > > On 04/30/2015 12:45 AM, Felipe Balbi wrote: > > >>>try setting nofua parameter. Windows always sets FUA bit (so all writes > > >>>> >are*always* flushed to non-volatile media), but telling mass storage > > >>>> >gadget to ignore FUA bit, you get better performance. > > >>> > > >>>At the expense of possibly loosing your data if you loose power, so > > >>>ignore it at your own peril:) > > >Well, unless you're completely powered via USB and have no batteries, > > >then yeah, you have an issue. The likelyhood that you have batteries is > > >much, much larger, though. > > > > Thanks for the help. However, enable nofua seems not helping performance > > with Win7 host. My command is: > > modprobe g_mass_storage file=/dev/mmcblk0p4 removable=1 nofua=1 > > then you're really on your own. I would suggest a sniffer to figure out > if the host isn't sending tokens fast enough (too many SOFs) or the > device isn't fast enough (too many NAKs/NYETs). oh yeah, if you can reproduce the same thing using a recent kernel (v4.0, for example) and give us further details of your setup (which platform, which controller you're using, etc), then linux-usb will be very happy to help out. -- balbi
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