Hi Alan, On Saturday, September 28, 2019 01:08, Alan Stern wrote: > > On Tue, 24 Sep 2019, Ran Wang wrote: > > > Hi Greg, > > > > On Monday, September 23, 2019 19:07, Greg Kroah-Hartman wrote: > > > > > > On Mon, Sep 23, 2019 at 06:51:02PM +0800, Ran Wang wrote: > > > > USB 2.0 Embedded Host PET Automated Test (CH6) 6.7.23 A-UUT > > > > "Unsupported Device" Message require to stop enumerating device > > > > with VID=0x1a0a PID=0x0201 and pop message to declare this device > > > > is not > > > supported. > > > > > > Why is this a requirement? > > > > This comes from <USB On-The-Go and Embedded Host Automated Compliance > > Plan for the On-The-Go& Embedded Host Supplement Revision2.0> > > How much do we care about our support for USB OTG? Isn't it dying off? As I know, some vendors still want to pass this Embedded Host compliance test to make sure their product's quality. And above test case is included. > > Below is related description I quote from it: > > 6.7.23 A-UUT "Unsupported Device" Message > > Purpose: This test verifies that an A-UUT produces a device non-supported > error message > > when a device it doesn't recognize, and does not support HNP, connects > to it. > > Applies to: All Targeted Hosts > > Description: Get VBUS turned on, and connect to the A-UUT. Get enumerated > and respond > > as an unknown device not supporting HNP. Check that a suitable error > message is generated. > > Pass Criteria: Message "Unsupported Device"or similar is displayed on > > UUT > > > > 6.7.23.1 Test Procedure > > 1. Start with cable still attached, PET applying 10 F capacitance and 10k pull- > down > > resistance between VBUS and ground, data lines not pulled up. > > 2. Get VBUS turned on, using the method described in Section6.7.1. > > 3. Wait for almost TB_SVLD_BCON max (1s - 0.1s = 0.9s) from VBUS reaching > VOTG_SESS_VLD max. > > 4. Connect PET using D+ pull-up. > > 5. Allow A-UUT to enumerate PET, responding with a VID / PID combination > not on the TPL > > of the UUT and also with the OTG descriptor stating that it does not support > HNP. > > 6. Start 30s timer when Device Descriptor is read. > > 7. Display Message "Click OK if 'Unsupported Device' indication displayed on > UUT". > > 8. If operator clicks OK before 30s timer expires, then UUT passes test. > > 9. If 30selapses first, then UUT fails test. > > 10. PET disconnects by removing any termination on the data lines, but leaves > a capacitance of > > 10 F and a pull-down resistance of 10k connected across VBUS. > > 11. Wait 2s to allow disconnection to be detected. > > End of Test. > > In fact, the system should respond the same way to any unrecognized device > that doesn't support HNP, right? There's nothing special about these VID/PID > values. Yes, but I saw there are already some implementation in upstream kernel for this purpose, just PID different: drivers/usb/core/otg_whitelist.h function is_targeted() > > > And why those specific vid/pid values? What do they refer to? > > > > For step 5, we got the VID / PID number from USB IF certified > > lab(Allion.inc at Taiwang). Looks like this is a reserved ID pair and > > will not be allocated to any vendor for their products. So it's hence used for > this case test (like saying: you should be able to pop a not-support message for > this reserved VID&PID). > > Don't we do this already? Yes, but in function is_stargeted(), I found it's a little be different: Current upstream: VID = 0x1a0a, PID = 0x0200 Info from USB-IF certified lab: VID = 0x1a0a, PID = 0x0201 Regards, Ran > Alan Stern
