Hi, On Thu, Jul 02, 2015 at 12:51:54PM +0200, Gregory CLEMENT wrote: > Hello, > > When I use configs to configure the mass storage function for the > gadget, and when the device is plugged under Windows, then the > partition that I expose is well managed, but I also see 7 other gadget > in the device manager with error. > > This seven bogus gadget seems to be the 7 other LUN that are not > used. Indeed if I apply this dirty patch: > > diff --git a/drivers/usb/gadget/function/f_mass_storage.c b/drivers/usb/gadget/function/f_mass_storage.c > index 3cc109f..2b4ae98 100644 > --- a/drivers/usb/gadget/function/f_mass_storage.c > +++ b/drivers/usb/gadget/function/f_mass_storage.c > @@ -3511,7 +3511,8 @@ static struct usb_function_instance *fsg_alloc_inst(void) > rc = PTR_ERR(opts->common); > goto release_opts; > } > - rc = fsg_common_set_nluns(opts->common, FSG_MAX_LUNS); > +// rc = fsg_common_set_nluns(opts->common, FSG_MAX_LUNS); > + rc = fsg_common_set_nluns(opts->common, 1); > if (rc) > goto release_opts; > > Then there is no more gadget error under Windows. As the value of > FSG_MAX_LUNS is 8 and in my configuration I only use one partition, > then it makes sens that I see 7 bogus gadgets. > > I also saw that in the legacy driver, it was possible to modify the > number of LUN using the module parameter file_count. This has been reported. Michal was working on a fix, but the patch hasn't been applied yet. > There is no such parameter when using configfs. > > What would be the correct way to fix it? Making sure you don't lie to the other side of the cable :-) > I thought about enumerate how many LUN where configured through > configfs and then setting the exact number using fsg_common_set_nluns. yeah, that should be the way. > There is no problem at all under Linux so maybe it is jut the way how > the gadget is exposed through USB. no, we shouldn't really lie, this really needs fixing. > > I tested it on the kernel 3.17 and 4.1 using the musb of the SoC > AM335x. > > Thanks for your feedback. > > Gregory > > -- > Gregory Clement, Free Electrons > Kernel, drivers, real-time and embedded Linux > development, consulting, training and support. > http://free-electrons.com -- balbi
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