Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752636AbcLGBsF (ORCPT ); Tue, 6 Dec 2016 20:48:05 -0500 Received: from mail-pf0-f178.google.com ([209.85.192.178]:33845 "EHLO mail-pf0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752117AbcLGBsD (ORCPT ); Tue, 6 Dec 2016 20:48:03 -0500 From: John Stultz To: lkml Cc: John Stultz , Wei Xu , Guodong Xu , Amit Pundir , Rob Herring , John Youn , Douglas Anderson , Chen Yu , Kishon Vijay Abraham I , Felipe Balbi , Greg Kroah-Hartman , linux-usb@vger.kernel.org Subject: [RFC][PATCH] HACK: usb: dwc2: Workaround case where GOTGCTL state is wrong Date: Tue, 6 Dec 2016 17:47:58 -0800 Message-Id: <1481075278-17600-1-git-send-email-john.stultz@linaro.org> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2293 Lines: 67 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 Cc: Guodong Xu Cc: Amit Pundir Cc: Rob Herring Cc: John Youn Cc: Douglas Anderson Cc: Chen Yu Cc: Kishon Vijay Abraham I Cc: Felipe Balbi Cc: Greg Kroah-Hartman Cc: linux-usb@vger.kernel.org Signed-off-by: John Stultz --- 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