> On Tue, 2014-06-17 at 12:19 +0200, Vlad Ungureanu wrote: > > > On Tue, 2014-06-17 at 11:18 +0200, Vlad Ungureanu wrote: > > > > > > > > > > > > > If that is not your intention, then you need to be more specific in the match table. > > > > Yes, it matches the whole device so that is why every interface gets probed. I > > > > will change that. > > > > > > That's problematic. You need to find out what happens if both interfaces > > > are used at the same time. > > > > My device has 2 interfaces in normal mode and 2 interfaces in ADK mode. > > Interface 0 has just ep0 which is control endpoint. Interface 1 has 2 bulk EPs: > > IN, OUT. I should check the macro how to define them nicely in the device > > table. > > No, don't do that. > > First of all, you are conflating two issues. > Switching between normal and ADK mode should indeed be done in user > space. How is it done in fact? To go into ADK mode the host needs to send the Android device a series of usb control messages with different data. This yes can be done from userspace but when the device goes into the ADK mode I need to handle it into Kernel space. The end goal of the project is to simulate the displayLink driver using an Android device instead of a DisplayLink compatible screen. In ADK mode I will need just interface 1 which has 2 bulk EPs. No other interaction from userspace will be with the device in ADK mode. > > Secondly the interfaces. Restricting the matching creates a problem > in cooperation with usbfs. At least if you both need them, like btusb > or the CDC drivers. > > Suppose you need both interfaces. Then you need to claim both interfaces > in probe(). However interfaces can be claimed from user space also > and freed in arbitrary order. > Now, if you change your matching so that you match only on the first > interface, binding will fail if user spaces unclaims the first > interface before the second. That's because your probe needs to fail > as the second interface is still claimed by user space. You can solve > this issue by matching on both interfaces and claiming the corresponding > interface in probe() In probe as I see it now I should claim just interface 1 because the Android Open Accessory standard does not offer support of communication over ep0 when in ADK mode so it would be useless. > > Regards > Oliver > > > -- > 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 -- Vlad Ungureanu
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