Hi, Thinh Nguyen writes: >> Felipe Balbi writes: >>> Thinh Nguyen writes: >>>> This patch fixes a commit that causes a hang from device waiting for >>>> data with the wrong sequence number. The commit ffb80fc672c3 ("usb: >>>> dwc3: gadget: skip Set/Clear Halt when invalid") adds a check to return >>>> early depending on DWC3_EP_STALL is set or not, prevent sending the ep >>>> halt command to HW endpoint to do CLEAR_FEATURE(ENDPOINT_HALT) request. >>>> This was to workaround the issue for macOS where the device hangs from >>>> sending DWC3 clear stall command. >>>> >>>> In USB 3.1 spec, 9.4.5, CLEAR_FEATURE(ENDPOINT_HALT) request always >>>> results in the data sequence being reinitialized to zero regardless >>>> whether the endpoint has been halted or not. Some device class depends >>>> on this feature for its protocol. For instance, in mass storage class, >>>> there is MSC reset protocol that does CLEAR_FEATURE(ENDPOINT_HALT) on >>>> bulk endpoints. This protocol reinitializes the data sequence and >>>> ensures that whatever pending data requested from previous CBW will be >>>> reset. Otherwise this will cause a hang as the device can wait for the >>>> data with the wrong sequence number from the previous CBW. We found this >>>> failure in USB CV: MSC Error Recovery Test with f_mass_storage. >>>> >>>> This patch fixes this issue by checking to see whether the set/halt ep >>>> call is a protocol call before early exit to make sure that set/clear >>>> halt endpoint command can go through if it is a device class protocol. >>>> >>>> Fixes: ffb80fc672c3 ("usb: dwc3: gadget: skip Set/Clear Halt when invalid") >>>> Signed-off-by: Thinh Nguyen >>> >>> this will regress the macOS case I wrote that commit for. We need to >> >> no wait, it won't regress macOS, but we're still left with the problem >> of host and peripheral being able to get DataToggle/SeqN out of sync. >> > > This patch is for the regression we have. Can you provide more > information for the macOS? I'm not sure if this is the case for macOS, I need to find a way to reproduce it again first. When I first reproduced it was with dwc3 running adb and connecting it to a macOS machine. > but maybe there is still pending transfer when it tries to send the > request? (There shouldn't be any before issuing ClearStall command). Do this could be, I don't remember if I checked this or not :-) Really, the best way here, IMHO, would be to re-verify what's going on with macOS and revert my orignal patch since it's, rather clearly, wrong. -- balbi