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| author |   Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> | 2018-11-09 20:44:36 +0900 |
|---|---|---|
| committer |   Felipe Balbi <felipe.balbi@linux.intel.com> | 2018-11-26 09:06:32 +0200 |
| commit | ceb94bc52c437463f0903e61060a94a2226fb672 (patch) | |
| tree | b4cc6a60fd5a80ce7a83d0dccf3c4ed2db99ccb7 /drivers/usb/gadget/function/uvc_queue.c | |
| parent | usb: dwc3: drd: Add support for DR detection through extcon (diff) | |
| download | wireguard-linux-ceb94bc52c437463f0903e61060a94a2226fb672.tar.xz wireguard-linux-ceb94bc52c437463f0903e61060a94a2226fb672.zip | |
usb: gadget: udc: renesas_usb3: add a safety connection way for forced_b_device
This patch adds a safety connection way for "forced_b_device" with
"workaround_for_vbus" like below:
< Example for R-Car E3 Ebisu >
# modprobe <any usb gadget driver>
# echo 1 > /sys/kernel/debug/ee020000.usb/b_device
(connect a usb cable to host side.)
# echo 2 > /sys/kernel/debug/ee020000.usb/b_device
Previous code should have connected a usb cable before the "b_device"
is set to 1 on the Ebisu board. However, if xHCI driver on the board
is probed, it causes some troubles:
- Conflicts USB VBUS/signals between the board and another host.
- "Cannot enable. Maybe the USB cable is bad?" might happen on
both the board and another host with a usb hub.
- Cannot enumerate a usb gadget correctly because an interruption
of VBUS change happens unexpectedly.
Reported-by: Kazuya Mizuguchi <kazuya.mizuguchi.ks@renesas.com>
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Diffstat (limited to 'drivers/usb/gadget/function/uvc_queue.c')
0 files changed, 0 insertions, 0 deletions