Messages in this thread | | | Subject | Re: [PATCH v3 1/1] usb: xhci: Add Clear_TT_Buffer | From | Jim Lin <> | Date | Thu, 2 May 2019 20:32:56 +0800 |
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On 2019年05月02日 18:56, Mathias Nyman wrote: > On 30.4.2019 6.06, 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". > > Good point, xhci isn't making sure TT buffers get cleared when they > should. > >> >> 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 add Clear_TT_Buffer for the following Set_Interface requests >> to get ACK successfully. >> >> Signed-off-by: Jim Lin <jilin@nvidia.com> >> --- >> v2: xhci_clear_tt_buffer_complete: add static, shorter indentation >> , remove its claiming in xhci.h >> v3: Add description for clearing_tt (xhci.h) >> >> drivers/usb/host/xhci-ring.c | 28 ++++++++++++++++++++++++++++ >> drivers/usb/host/xhci.c | 7 +++++++ >> drivers/usb/host/xhci.h | 2 ++ >> 3 files changed, 37 insertions(+) >> >> diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c >> index 9215a28dad40..02b1ebad81e7 100644 >> --- a/drivers/usb/host/xhci-ring.c >> +++ b/drivers/usb/host/xhci-ring.c >> @@ -1786,6 +1786,33 @@ struct xhci_segment *trb_in_td(struct xhci_hcd >> *xhci, >> return NULL; >> } >> +static void xhci_clear_hub_tt_buffer(struct xhci_hcd *xhci, >> + unsigned int slot_id, struct xhci_td *td) >> +{ >> + struct xhci_virt_device *dev; >> + struct xhci_slot_ctx *slot_ctx; >> + int saved_devnum; >> + >> + /* >> + * As part of low/full-speed endpoint-halt processing >> + * we must clear the TT buffer (USB 2.0 specification 11.17.5). >> + */ >> + if (td->urb->dev->tt && !usb_pipeint(td->urb->pipe) && >> + (td->urb->dev->tt->hub != xhci_to_hcd(xhci)->self.root_hub) && >> + !xhci->clearing_tt) { >> + xhci->clearing_tt = 1; > > one xhci->clearing_tt under is not enough, there might be several HS > hubs, or > multi TT hubs with halted endpoints at the same time that need TT > clearing. > > How about a flag per endpoint? > > For example Aadding a EP_CLEARING_TT flag for ep_state in struct > xhci_virt_ep? > just like EP_STOP_CMD_PENDING, or EP_HALTED > >> + dev = xhci->devs[slot_id]; >> + slot_ctx = xhci_get_slot_ctx(xhci, dev->out_ctx); >> + /* Update devnum temporarily for usb_hub_clear_tt_buffer */ >> + saved_devnum = td->urb->dev->devnum; >> + td->urb->dev->devnum = (int) le32_to_cpu(slot_ctx->dev_state) & >> + DEV_ADDR_MASK; > > Changing the struct usb_device devnum on the fly seems like a bit of a > hack, and probably > causes issues elsewhere. Devnum is tied to uevents, usbfs, sysfs etc. > > We need another solution, some options: > > - Let usb_hub_clear_tt_buffer() figure out address and not just use > devnum if host == xhci. > - Add address to struct usb_device, (would have both address and > devnum), use it when needed. > - Provide address as parameter to usb_clear_tt_buffer() (api change, > changes other host drivers) > - Force devnum to be same as address, usb core can't choose address > for xhci devices. > > -Mathias Thanks for review. Will try.
--nvpublic
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