Hi, On Wed, Oct 30, 2013 at 03:17:46PM +0100, Johannes Stezenbach wrote: > Hi, > > I'm testing dwc3 with g_zero and noticed that errors > seem to stick even after SET_CONFIGURATION/SET_INTERFACE. > > In f_sourcesink.c, check_read_data() calls usb_ep_set_halt() > if the data does not match the expected values, and > sourcesink_set_alt() indirectly calls usb_ep_disable() > and usb_ep_enable(). > > Now, include/linux/usb/gadget.h comments for usb_ep_enable() > are not 100% clear wrt STALL, except "making it usable" > sounds like it should clear it. However, usb_ep_set_halt() > comments states: > > * Note that while an endpoint CLEAR_FEATURE will be invisible to the > * gadget driver, a SET_INTERFACE will not be. To reset endpoints for the > * current altsetting, see usb_ep_clear_halt(). When switching altsettings, > * it's simplest to use usb_ep_enable() or usb_ep_disable() for the endpoints. > > That suggests to me that sourcesink_set_alt() is correct to > simply call usb_ep_enable(), i.e. no explicit usb_ep_clear_halt() > is needed? If so it would mean dwc3 ep_enable() is buggy. we clear those flags on usb_ep_disable(). You can't enable an endpoint which is already enabled. And you can see that when you're going to switch alt settings, f_sourcesink calls disable_source_sink() which will call disable_endpoints() which will disable each and every endpoint, thus clearing the such flags. Do you have any patches on f_sourcesink which might have caused this bug ? -- balbi
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