From patchwork Tue Mar 10 12:38:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 11429321 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7E925139A for ; Tue, 10 Mar 2020 13:24:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5E5222468C for ; Tue, 10 Mar 2020 13:24:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583846681; bh=ZBMgcPbP3wxgjFwxzZhy0vyba5otvsXz9ItW6/9bml8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=qwmxrRcKgPyuSZDlUoEfXUlM+3puTeb3IpN7kNsl7JXj1TvvGfR/fEmQDfTxmy0NG 9OrZ9OwwOp4DAr0eTuge/nU9l65QERBPoM6VBhLSdG+MFFItvmvVas1b41FVFmMx0S Yd0cPdQtv44UGOAF9K2GcqROvaeYJINtW0x5kqFk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729885AbgCJNYh (ORCPT ); Tue, 10 Mar 2020 09:24:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:39156 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727391AbgCJM6z (ORCPT ); Tue, 10 Mar 2020 08:58:55 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id DE8402467D; Tue, 10 Mar 2020 12:58:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583845134; bh=ZBMgcPbP3wxgjFwxzZhy0vyba5otvsXz9ItW6/9bml8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=njbnNr8AHnWPRicAIzghvD1XpZHYMQY4x/iJ9J7mg9VVAE0m/Vut3kaJLlKx0v1wJ oN+KXQqUQ5IWsG06yJEh3bKEXAUHrQiJNv7K5useJw7nf3abD8zXTIfZ0yxzyXvWLf I3UmabrBSpb19iyudhU1qhBrs7V0DVx73J4MzAEQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Felipe Balbi , Yang Fei , Thinh Nguyen , Tejas Joglekar , Andrzej Pietrasiewicz , Jack Pham , Todd Kjos , Linux USB List , Pratham Pratap , John Stultz Subject: [PATCH 5.5 072/189] usb: dwc3: gadget: Update chain bit correctly when using sg list Date: Tue, 10 Mar 2020 13:38:29 +0100 Message-Id: <20200310123646.891832602@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200310123639.608886314@linuxfoundation.org> References: <20200310123639.608886314@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org From: Pratham Pratap commit dad2aff3e827b112f27fa5e6f2bf87a110067c3f upstream. If scatter-gather operation is allowed, a large USB request is split into multiple TRBs. For preparing TRBs for sg list, driver iterates over the list and creates TRB for each sg and mark the chain bit to false for the last sg. The current IOMMU driver is clubbing the list of sgs which shares a page boundary into one and giving it to USB driver. With this the number of sgs mapped it not equal to the the number of sgs passed. Because of this USB driver is not marking the chain bit to false since it couldn't iterate to the last sg. This patch addresses this issue by marking the chain bit to false if it is the last mapped sg. At a practical level, this patch resolves USB transfer stalls seen with adb on dwc3 based db845c, pixel3 and other qcom hardware after functionfs gadget added scatter-gather support around v4.20. Credit also to Anurag Kumar Vulisha who implemented a very similar fix to this issue. Cc: Felipe Balbi Cc: Yang Fei Cc: Thinh Nguyen Cc: Tejas Joglekar Cc: Andrzej Pietrasiewicz Cc: Jack Pham Cc: Todd Kjos Cc: Greg KH Cc: Linux USB List Cc: stable #4.20+ Signed-off-by: Pratham Pratap [jstultz: Slight tweak to remove sg_is_last() usage, reworked commit message, minor comment tweak] Signed-off-by: John Stultz Link: https://lore.kernel.org/r/20200302214443.55783-1-john.stultz@linaro.org Signed-off-by: Greg Kroah-Hartman --- drivers/usb/dwc3/gadget.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -1068,7 +1068,14 @@ static void dwc3_prepare_one_trb_sg(stru unsigned int rem = length % maxp; unsigned chain = true; - if (sg_is_last(s)) + /* + * IOMMU driver is coalescing the list of sgs which shares a + * page boundary into one and giving it to USB driver. With + * this the number of sgs mapped is not equal to the number of + * sgs passed. So mark the chain bit to false if it isthe last + * mapped sg. + */ + if (i == remaining - 1) chain = false; if (rem && usb_endpoint_dir_out(dep->endpoint.desc) && !chain) {