On Mon, 2016-12-05 at 12:06 +0200, Felipe Balbi wrote: > Hi, > > Todd Brandt <todd.e.bra...@linux.intel.com> writes: > > Add a module parameter that replaces the USB_RESUME_TIMEOUT > > and other hardcoded delay numbers with the USB spec minimums. > > By default the patch retains the current values. > > > > The USB subsystem currently uses heavily padded values for TDRSMDN > > and TRSTRCY. This patch keeps the current values by default, but if > > there's a reason for that. We've found many broken devices over the > years and a lot of inconsistencies were also found while with host > controller A or B or C, because they all used different timings. > > Using spec minimum is, actually, a recipe for disaster :-) There's no > way we can guarantee all devices currently in use are respecting that > part of the spec. > > This is a very fragile part of the USB spec which different folks have > different understanding and that's why so many devices are "broken". > > I'd be careful with such a patchset. It's a nice idea, but I'd be > careful :-) > Hi Felipe, I agree that there are a collection of corner cases that will fail if we use the minimums, but do you object to providing the option to use minimums? My focus is on platform developers looking to optimize a specific device build where the range of USB devices is known in advance.
Another plus is this patch could be further configured to increase the delay values for buggy devices. I just like the idea of being able to easily change all the timing values. -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
