Messages in this thread Patch in this message | | | From | John Stultz <> | Subject | [RFC][PATCH] HACK: usb: dwc2: Workaround case where GOTGCTL state is wrong | Date | Tue, 6 Dec 2016 17:47:58 -0800 |
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Hey John, Just wanted to send this by you, as it seems something is slightly off with the GOTGCTL state when removing a otg adapter cable. The following seems to work around the issue I'm seeing.
Let me know if you have any thoughts on this. thanks -john
When removing a USB-A to USB-otg adapter cable, we get a change status irq, and then in dwc2_conn_id_status_change, we erroniously see the GOTGCTL_CONID_B flag set. This causes us to get stuck in the "while (!dwc2_is_device_mode(hsotg))" loop, spitting out "Waiting for Peripheral Mode, Mode=Host" warnings until it fails out many seconds later.
This patch works around the issue by re-reading the GOTGCTL state to check if the GOTGCTL_CONID_B is still set and if not restarting the change status logic.
I suspect this isn't the best solution, but it seems to work well for me.
Feedback would be greatly appreciated!
Cc: Wei Xu <xuwei5@hisilicon.com> Cc: Guodong Xu <guodong.xu@linaro.org> Cc: Amit Pundir <amit.pundir@linaro.org> Cc: Rob Herring <robh+dt@kernel.org> Cc: John Youn <johnyoun@synopsys.com> Cc: Douglas Anderson <dianders@chromium.org> Cc: Chen Yu <chenyu56@huawei.com> Cc: Kishon Vijay Abraham I <kishon@ti.com> Cc: Felipe Balbi <felipe.balbi@linux.intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: linux-usb@vger.kernel.org Signed-off-by: John Stultz <john.stultz@linaro.org> --- drivers/usb/dwc2/hcd.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c index 143da47..6d6802a 100644 --- a/drivers/usb/dwc2/hcd.c +++ b/drivers/usb/dwc2/hcd.c @@ -3203,7 +3203,7 @@ static void dwc2_conn_id_status_change(struct work_struct *work) dev_dbg(hsotg->dev, "gotgctl=%0x\n", gotgctl); dev_dbg(hsotg->dev, "gotgctl.b.conidsts=%d\n", !!(gotgctl & GOTGCTL_CONID_B)); - +again: /* B-Device connector (Device Mode) */ if (gotgctl & GOTGCTL_CONID_B) { /* Wait for switch to device mode */ @@ -3219,6 +3219,9 @@ static void dwc2_conn_id_status_change(struct work_struct *work) dwc2_is_host_mode(hsotg) ? "Host" : "Peripheral"); usleep_range(20000, 40000); + gotgctl = dwc2_readl(hsotg->regs + GOTGCTL); + if (!(gotgctl & GOTGCTL_CONID_B)) + goto again; if (++count > 250) break; } -- 2.7.4
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