From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753363AbdJaN0K (ORCPT ); Tue, 31 Oct 2017 09:26:10 -0400 Received: from fllnx210.ext.ti.com ([198.47.19.17]:61353 "EHLO fllnx210.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751926AbdJaN0J (ORCPT ); Tue, 31 Oct 2017 09:26:09 -0400 From: Roger Quadros To: CC: , , , , Roger Quadros Subject: [PATCH] ARM: dts: dra7: Disable USB metastability workaround for USB2 Date: Tue, 31 Oct 2017 15:26:00 +0200 Message-ID: <1509456360-2638-1-git-send-email-rogerq@ti.com> X-Mailer: git-send-email 2.7.4 MIME-Version: 1.0 Content-Type: text/plain X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The metastability workaround causes Erratic errors [1] on the HighSpeed USB PHY which can cause upto 2 seconds delay in enumerating to a USB host while in Gadget mode. Disable the Run/Stop metastability workaround to avoid this ill effect. We are aware that this opens up the opportunity for Run/Stop metastability, however this issue has never been observed in TI releases so we think that Run/Stop metastability is a lesser evil than the PHY Erratic errors. So disable it. [1] USB controller trace during gadget enumeration irq/90-dwc3-969 [000] d... 52.323145: dwc3_event: event (00000901): Erratic Error [U0] irq/90-dwc3-969 [000] d... 52.560646: dwc3_event: event (00000901): Erratic Error [U0] irq/90-dwc3-969 [000] d... 52.798144: dwc3_event: event (00000901): Erratic Error [U0] Signed-off-by: Roger Quadros --- arch/arm/boot/dts/dra7.dtsi | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm/boot/dts/dra7.dtsi b/arch/arm/boot/dts/dra7.dtsi index 02a136a..1264e39 100644 --- a/arch/arm/boot/dts/dra7.dtsi +++ b/arch/arm/boot/dts/dra7.dtsi @@ -1540,6 +1540,7 @@ dr_mode = "otg"; snps,dis_u3_susphy_quirk; snps,dis_u2_susphy_quirk; + snps,dis_metastability_quirk; }; }; -- cheers, -roger Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki