On 3.6.2019 13.53, Jim Lin wrote:
USB 2.0 specification chapter 11.17.5 says "as part of endpoint halt
processing for full-/low-speed endpoints connected via a TT, the host
software must use the Clear_TT_Buffer request to the TT to ensure
that the buffer is not in the busy state".
In our case, a full-speed speaker (ConferenceCam) is behind a high-
speed hub (ConferenceCam Connect), sometimes once we get STALL on a
request we may continue to get STALL with the folllowing requests,
like Set_Interface.
Here we invoke usb_hub_clear_tt_buffer() to send Clear_TT_Buffer
request to the hub of the device for the following Set_Interface
requests to the device to get ACK successfully.
Signed-off-by: Jim Lin <jilin@xxxxxxxxxx>
---
v2: xhci_clear_tt_buffer_complete: add static, shorter indentation
, remove its claiming in xhci.h
v3: Add description for clearing_tt (xhci.h)
v4: Remove clearing_tt flag because hub_tt_work has hub->tt.lock
to protect for Clear_TT_Buffer to be run serially.
Remove xhci_clear_tt_buffer_complete as it's not necessary.
Same reason as the above.
Extend usb_hub_clear_tt_buffer parameter
v5: Not extending usb_hub_clear_tt_buffer parameter
Add description.
v6: Remove unused parameter slot_id from xhci_clear_hub_tt_buffer
v7: Add devaddr field in "struct usb_device"
v8: split as two patches
v9: no change flag
v10: Add EP_CLEARING_TT flag
v11: Add spin_lock/unlock in xhci_clear_tt_buffer_complete
drivers/usb/host/xhci-ring.c | 27 ++++++++++++++++++++++++++-
drivers/usb/host/xhci.c | 21 +++++++++++++++++++++
drivers/usb/host/xhci.h | 5 +++++
3 files changed, 52 insertions(+), 1 deletion(-)
xhci parts look good to me,
In case Greg wants to pick up both the core changes (1/2) and
the xhci changes (2/2) at the same time:
Acked-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
