Hi, Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx> 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 <thinhn@xxxxxxxxxxxx> this will regress the macOS case I wrote that commit for. We need to FIRST figure out why ClearStall command times out. Have you done that? Do you have a testcase which constantly issues ClearFeature(ENDPOINT_HALT) to a single endpoint and can verify that it doesn't time out? Why does it timeout on macOS? -- balbi
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