From nobody Sun Feb 8 04:57:29 2026 Received: from mail-pj1-f73.google.com (mail-pj1-f73.google.com [209.85.216.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 518A61119A for ; Sat, 8 Feb 2025 03:31:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.73 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738985494; cv=none; b=D/Y513qf1Sab+J7LHD3JSOlXcoJUT+pjW5K17Uc3Grc8HZyuiPhSsR1xROhPlkMeVwQDlYvorc2Ub6QIrowNQc8I6aPMsIF/wXennOoN8kol6+TTWlqJRzxU2b/Bts73VUcAvEZ65b5YdGuvFQdB93NGHS+mwAXDEDLjtQxfjko= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738985494; c=relaxed/simple; bh=+sardm/LolQw6ziPvWfFf1wd1dVDkIErwNJaVuBhKCI=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=FPBb3jHieIv12nXuQ9uJIrQm9MVppJPTb4x8t7/+570i43LXMvxJEu07YHvRto41KUmTeL2EOkdg2PPssFfTccY2BY9BE6SUJZ+3fjCfU9WKaHAmT//9kuRMZg0Nv1tTHutp/uzh9NxIgZyOro9Qm4hapg63wA7bB315KxGNwfM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--badhri.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=LJFz7KrD; arc=none smtp.client-ip=209.85.216.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--badhri.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="LJFz7KrD" Received: by mail-pj1-f73.google.com with SMTP id 98e67ed59e1d1-2fa166cf656so4364327a91.2 for ; Fri, 07 Feb 2025 19:31:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1738985492; x=1739590292; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=p0gZ2q9HM3rX07kpmvYyR39VyXsdRnL4CUz3gU+Woqc=; b=LJFz7KrDHsIKgE1KF5CTCVOYMs+coq4m0/ipl0e6pW7LQ5n6CX5+40/KgcCubxkXm3 o94Q9oPCMQYLHH3a9NPJ1hTK6ZxI1wQIyavXF3Fv8LQxJGlwLwaBV9p7bgxfYS9kTeI9 s14fgdWz8kX9U6R7cYZenisjEB/wRDRODQ5CCgeJUPGxpCqtuPirEo4n51djQcK8UEtb IFiT4Zk3vbUW39kEGzWFR9pov6wBVCNcqMqesMC1VRNo2VQV6ixvvUpOH0929BVuFMR6 52os5NztoupKNjWx3tpVkD1xezoWWz3zou9zgCdxl4cT1AhCPHvJgmBnlamDUrpNwR8S kvMA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1738985492; x=1739590292; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=p0gZ2q9HM3rX07kpmvYyR39VyXsdRnL4CUz3gU+Woqc=; b=vII4z8swsvESIKRYcdiOJTUUVB6o44QdVigaxbMXmfflO4RdnPF5Ml+LI5n+fzhlyD Y9lWa7lAE598d9CINK9Y4gPvexDj/vzs6rpXHFkbapGAE05450QLElAozVCmm0Yokveg A/re375mukQd0hIPj8Zc53Ez9D/6T5rUpptOnivNThGtiXWQBLptb3s9wBfziBqC/GCy nNyGaQLFIz8PKV9e+0N8WF5Y1O7DaUZhVyUa3uNggWYPTd96/spVT0YkvZY87dHS/0cL MJZBBmuCNbjDNhaaD5qlEkHDTMyD3BsS08ubqKmzByLgpUomCD48+8cdYfGlsY6ZsyBW tRSw== X-Forwarded-Encrypted: i=1; AJvYcCXtJehmerAg6Z3BzPf8Ts+vs7+BKM7ZnQ3cIJMlpU/Fh6JGqjj0R+b0U9TRG29tC/aLeUDT+Lxx8u9kGl8=@vger.kernel.org X-Gm-Message-State: AOJu0YxcDnJvdlBTVPZMdK5rHcs22WjScbjgHg8jlUrIRXt7RAAhb0iF 37DH9PCtYIOV/DLk1qf0zM41ULoZeKO8tcw2T7GXoudp6yem97bH58reQIb7GyM8wopoAwbzvOu jvA== X-Google-Smtp-Source: AGHT+IHF6JQH1xgZnqdPNtMVklKecXq5Aajik4oseZpvmg90/Ega/bv/OBxCXP5JoMVF9e7hXVZw8+bCgNQ= X-Received: from pjbsp15.prod.google.com ([2002:a17:90b:52cf:b0:2ee:53fe:d0fc]) (user=badhri job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:2d8c:b0:2f9:9ddd:689b with SMTP id 98e67ed59e1d1-2fa242e75eamr7097462a91.22.1738985492599; Fri, 07 Feb 2025 19:31:32 -0800 (PST) Date: Sat, 8 Feb 2025 03:31:29 +0000 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.48.1.502.g6dc24dfdaf-goog Message-ID: <20250208033129.3524423-1-badhri@google.com> Subject: [PATCH v2] usb: dwc3: gadget: Prevent irq storm when TH re-executes From: Badhri Jagan Sridharan To: Thinh.Nguyen@synopsys.com, gregkh@linuxfoundation.org, felipe.balbi@linux.intel.com Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, jameswei@google.com, Badhri Jagan Sridharan , stable@kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" While commit d325a1de49d6 ("usb: dwc3: gadget: Prevent losing events in event cache") makes sure that top half(TH) does not end up overwriting the cached events before processing them when the TH gets invoked more than one time, returning IRQ_HANDLED results in occasional irq storm where the TH hogs the CPU. The irq storm can be prevented by clearing the flag before event handler busy is cleared. Default enable interrupt moderation in all versions which support them. ftrace event stub during dwc3 irq storm: irq/504_dwc3-1111 ( 1111) [000] .... 70.000866: irq_handler_exit: irq= =3D14 ret=3Dhandled irq/504_dwc3-1111 ( 1111) [000] .... 70.000872: irq_handler_entry: irq= =3D504 name=3Ddwc3 irq/504_dwc3-1111 ( 1111) [000] .... 70.000874: irq_handler_exit: irq= =3D504 ret=3Dhandled irq/504_dwc3-1111 ( 1111) [000] .... 70.000881: irq_handler_entry: irq= =3D504 name=3Ddwc3 irq/504_dwc3-1111 ( 1111) [000] .... 70.000883: irq_handler_exit: irq= =3D504 ret=3Dhandled irq/504_dwc3-1111 ( 1111) [000] .... 70.000889: irq_handler_entry: irq= =3D504 name=3Ddwc3 irq/504_dwc3-1111 ( 1111) [000] .... 70.000892: irq_handler_exit: irq= =3D504 ret=3Dhandled irq/504_dwc3-1111 ( 1111) [000] .... 70.000898: irq_handler_entry: irq= =3D504 name=3Ddwc3 irq/504_dwc3-1111 ( 1111) [000] .... 70.000901: irq_handler_exit: irq= =3D504 ret=3Dhandled irq/504_dwc3-1111 ( 1111) [000] .... 70.000907: irq_handler_entry: irq= =3D504 name=3Ddwc3 irq/504_dwc3-1111 ( 1111) [000] .... 70.000909: irq_handler_exit: irq= =3D504 ret=3Dhandled irq/504_dwc3-1111 ( 1111) [000] .... 70.000915: irq_handler_entry: irq= =3D504 name=3Ddwc3 irq/504_dwc3-1111 ( 1111) [000] .... 70.000918: irq_handler_exit: irq= =3D504 ret=3Dhandled irq/504_dwc3-1111 ( 1111) [000] .... 70.000924: irq_handler_entry: irq= =3D504 name=3Ddwc3 irq/504_dwc3-1111 ( 1111) [000] .... 70.000927: irq_handler_exit: irq= =3D504 ret=3Dhandled irq/504_dwc3-1111 ( 1111) [000] .... 70.000933: irq_handler_entry: irq= =3D504 name=3Ddwc3 irq/504_dwc3-1111 ( 1111) [000] .... 70.000935: irq_handler_exit: irq= =3D504 ret=3Dhandled .... Cc: stable@kernel.org Suggested-by: Thinh Nguyen Fixes: d325a1de49d6 ("usb: dwc3: gadget: Prevent losing events in event cac= he") Signed-off-by: Badhri Jagan Sridharan --- drivers/usb/dwc3/core.c | 2 +- drivers/usb/dwc3/gadget.c | 10 +++++++--- 2 files changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c index dfa1b5fe48dc..6df971ef7285 100644 --- a/drivers/usb/dwc3/core.c +++ b/drivers/usb/dwc3/core.c @@ -1835,7 +1835,7 @@ static void dwc3_get_properties(struct dwc3 *dwc) dwc->tx_thr_num_pkt_prd =3D tx_thr_num_pkt_prd; dwc->tx_max_burst_prd =3D tx_max_burst_prd; =20 - dwc->imod_interval =3D 0; + dwc->imod_interval =3D 1; =20 dwc->tx_fifo_resize_max_num =3D tx_fifo_resize_max_num; } diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index d27af65eb08a..fad115113d28 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -4467,14 +4467,18 @@ static irqreturn_t dwc3_process_event_buf(struct dw= c3_event_buffer *evt) dwc3_writel(dwc->regs, DWC3_GEVNTSIZ(0), DWC3_GEVNTSIZ_SIZE(evt->length)); =20 + evt->flags &=3D ~DWC3_EVENT_PENDING; + /* + * Add an explicit write memory barrier to make sure that the update of + * clearing DWC3_EVENT_PENDING is observed in dwc3_check_event_buf() + */ + wmb(); + if (dwc->imod_interval) { dwc3_writel(dwc->regs, DWC3_GEVNTCOUNT(0), DWC3_GEVNTCOUNT_EHB); dwc3_writel(dwc->regs, DWC3_DEV_IMOD(0), dwc->imod_interval); } =20 - /* Keep the clearing of DWC3_EVENT_PENDING at the end */ - evt->flags &=3D ~DWC3_EVENT_PENDING; - return ret; } =20 base-commit: 9682c35ff6ecd76d9462d4749b8b413d3e8e605e --=20 2.48.1.502.g6dc24dfdaf-goog