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* [PATCH v11 0/2] usb: xhci: Add Clear_TT_Buffer
@ 2019-06-03 10:53 Jim Lin
  2019-06-03 10:53 ` [PATCH v11 1/2] usb: Add devaddr in struct usb_device Jim Lin
                   ` (2 more replies)
  0 siblings, 3 replies; 10+ messages in thread
From: Jim Lin @ 2019-06-03 10:53 UTC (permalink / raw)
  To: gregkh, mathias.nyman, stern, kai.heng.feng, drinkcat,
	Thinh.Nguyen, nsaenzjulienne, jflat, malat
  Cc: linux-usb, linux-kernel, Jim Lin

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.

Solution is to 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.

The Clear_TT_Buffer request sent to the hub includes the address of
the LS/FS child device in wValue field. usb_hub_clear_tt_buffer()
uses udev->devnum to set the address wValue. This won't work for
devices connected to xHC.

For other host controllers udev->devnum is the same as the address of
the usb device, chosen and set by usb core. With xHC the controller
hardware assigns the address, and won't be the same as devnum.

Here we have two patches.
One is to add devaddr in struct usb_device for
usb_hub_clear_tt_buffer() to use.
Another is to invoke usb_hub_clear_tt_buffer() for halt processing.
 
Signed-off-by: Jim Lin <jilin@nvidia.com>

Jim Lin (2):
  usb: Add devaddr in struct usb_device
  usb: xhci: Add Clear_TT_Buffer

 drivers/usb/core/hub.c       |  4 +++-
 drivers/usb/host/xhci-ring.c | 27 ++++++++++++++++++++++++++-
 drivers/usb/host/xhci.c      | 23 +++++++++++++++++++++++
 drivers/usb/host/xhci.h      |  5 +++++
 include/linux/usb.h          |  2 ++
 5 files changed, 59 insertions(+), 2 deletions(-)

-- 
2.1.4


^ permalink raw reply	[flat|nested] 10+ messages in thread
* [PATCH v11 0/2] usb: xhci: Add Clear_TT_Buffer
@ 2019-05-29 14:55 Jim Lin
  0 siblings, 0 replies; 10+ messages in thread
From: Jim Lin @ 2019-05-29 14:55 UTC (permalink / raw)
  To: gregkh, mathias.nyman, stern, kai.heng.feng, drinkcat,
	Thinh.Nguyen, nsaenzjulienne, jflat, malat
  Cc: linux-usb, linux-kernel, Jim Lin

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.

Solution is to 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.

The Clear_TT_Buffer request sent to the hub includes the address of
the LS/FS child device in wValue field. usb_hub_clear_tt_buffer()
uses udev->devnum to set the address wValue. This won't work for
devices connected to xHC.

For other host controllers udev->devnum is the same as the address of
the usb device, chosen and set by usb core. With xHC the controller
hardware assigns the address, and won't be the same as devnum.

Here we have two patches.
One is to add devaddr in struct usb_device for
usb_hub_clear_tt_buffer() to use.
Another is to invoke usb_hub_clear_tt_buffer() for halt processing.
 
Signed-off-by: Jim Lin <jilin@nvidia.com>

Jim Lin (2):
  usb: Add devaddr in struct usb_device
  usb: xhci: Add Clear_TT_Buffer

 drivers/usb/core/hub.c       |  4 +++-
 drivers/usb/host/xhci-ring.c | 27 ++++++++++++++++++++++++++-
 drivers/usb/host/xhci.c      | 23 +++++++++++++++++++++++
 drivers/usb/host/xhci.h      |  5 +++++
 include/linux/usb.h          |  2 ++
 5 files changed, 59 insertions(+), 2 deletions(-)

-- 
2.1.4


^ permalink raw reply	[flat|nested] 10+ messages in thread

end of thread, other threads:[~2019-06-05  9:48 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-06-03 10:53 [PATCH v11 0/2] usb: xhci: Add Clear_TT_Buffer Jim Lin
2019-06-03 10:53 ` [PATCH v11 1/2] usb: Add devaddr in struct usb_device Jim Lin
2019-06-05  9:48   ` Jim Lin
2019-06-03 10:53 ` [PATCH v11 2/2] usb: xhci: Add Clear_TT_Buffer Jim Lin
2019-06-03 12:35   ` Mathias Nyman
2019-06-03 12:23 ` [PATCH v11 0/2] " Greg KH
2019-06-04  8:53   ` Jim Lin
2019-06-04  8:59     ` Greg KH
2019-06-04 14:22     ` Alan Stern
  -- strict thread matches above, loose matches on Subject: below --
2019-05-29 14:55 Jim Lin

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