From nobody Wed Dec 17 17:28:11 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 946D0C61D85 for ; Thu, 23 Nov 2023 08:20:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344899AbjKWIUF (ORCPT ); Thu, 23 Nov 2023 03:20:05 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42136 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229543AbjKWIUB (ORCPT ); Thu, 23 Nov 2023 03:20:01 -0500 Received: from hi1smtp01.de.adit-jv.com (smtp1.de.adit-jv.com [93.241.18.167]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 81DC9B9; Thu, 23 Nov 2023 00:20:07 -0800 (PST) Received: from hi2exch02.adit-jv.com (hi2exch02.adit-jv.com [10.72.92.28]) by hi1smtp01.de.adit-jv.com (Postfix) with ESMTP id 825C2520165; Thu, 23 Nov 2023 09:20:05 +0100 (CET) Received: from vmlxhi-118.adit-jv.com (10.72.93.77) by hi2exch02.adit-jv.com (10.72.92.28) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.34; Thu, 23 Nov 2023 09:20:05 +0100 From: Hardik Gajjar To: , , CC: , , , , , , , , Subject: [PATCH] usb: hubs: Decrease IN-endpoint poll interval for Microchip USB491x hub Date: Thu, 23 Nov 2023 09:19:48 +0100 Message-ID: <20231123081948.58776-1-hgajjar@de.adit-jv.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 X-Originating-IP: [10.72.93.77] X-ClientProxiedBy: hi2exch02.adit-jv.com (10.72.92.28) To hi2exch02.adit-jv.com (10.72.92.28) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" There is a potential delay in announcing downstream USB bus activity to Linux USB drivers due to the default interrupt endpoint having a poll interval of 256ms. Microchip has recommended ignoring the device descriptor and reducing that value to 32ms, as it was too late to modify it in silicon. This patch aims to speed up the USB enumeration process, facilitating the successful completion of Apple CarPlay certifications and enhancing user experience when utilizing USB devices through the Microchip Multihost Hub. A new quirk, USB_QUIRK_REDUCE_FRAME_INTR_BINTERVAL, accelerates the notification process by changing the Endpoint interrupt poll interval from 256ms to 32ms. Signed-off-by: Hardik Gajjar --- Documentation/admin-guide/kernel-parameters.txt | 4 ++++ drivers/usb/core/config.c | 8 ++++++++ drivers/usb/core/quirks.c | 11 +++++++++++ include/linux/usb/quirks.h | 5 +++++ 4 files changed, 28 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentatio= n/admin-guide/kernel-parameters.txt index 65731b060e3f..6b0a66f0e6bf 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -6908,6 +6908,10 @@ pause after every control message); o =3D USB_QUIRK_HUB_SLOW_RESET (Hub needs extra delay after resetting its port); + p =3D USB_QUIRK_REDUCE_FRAME_INTR_BINTERVAL (Set + bInterval to a Maximum of 9 to Reduce + default Poll Rate from 256 ms to + 32 ms); Example: quirks=3D0781:5580:bk,0a5c:5834:gij =20 usbhid.mousepoll=3D diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c index b19e38d5fd10..4edbb5922872 100644 --- a/drivers/usb/core/config.c +++ b/drivers/usb/core/config.c @@ -355,6 +355,14 @@ static int usb_parse_endpoint(struct device *ddev, int= cfgno, n =3D clamp(fls(d->bInterval), i, j); i =3D j =3D n; } + + /* + * This quirk limits bInterval to 9 (32 ms). + */ + if (udev->quirks & USB_QUIRK_REDUCE_FRAME_INTR_BINTERVAL) { + n =3D clamp(fls(d->bInterval), i, min(j, 9)); + i =3D j =3D n; + } break; default: /* USB_SPEED_FULL or _LOW */ /* diff --git a/drivers/usb/core/quirks.c b/drivers/usb/core/quirks.c index 15e9bd180a1d..243ae5981cc8 100644 --- a/drivers/usb/core/quirks.c +++ b/drivers/usb/core/quirks.c @@ -138,6 +138,9 @@ static int quirks_param_set(const char *value, const st= ruct kernel_param *kp) case 'o': flags |=3D USB_QUIRK_HUB_SLOW_RESET; break; + case 'p': + flags |=3D USB_QUIRK_REDUCE_FRAME_INTR_BINTERVAL; + break; /* Ignore unrecognized flag characters */ } } @@ -211,6 +214,14 @@ static const struct usb_device_id usb_quirk_list[] =3D= { /* USB3503 */ { USB_DEVICE(0x0424, 0x3503), .driver_info =3D USB_QUIRK_RESET_RESUME }, =20 + /* USB491x hubs need 32ms instead of 256ms bInterval */ + { USB_DEVICE(0x0424, 0x4913), .driver_info =3D + USB_QUIRK_REDUCE_FRAME_INTR_BINTERVAL}, + { USB_DEVICE(0x0424, 0x4914), .driver_info =3D + USB_QUIRK_REDUCE_FRAME_INTR_BINTERVAL}, + { USB_DEVICE(0x0424, 0x4915), .driver_info =3D + USB_QUIRK_REDUCE_FRAME_INTR_BINTERVAL}, + /* Microsoft Wireless Laser Mouse 6000 Receiver */ { USB_DEVICE(0x045e, 0x00e1), .driver_info =3D USB_QUIRK_RESET_RESUME }, =20 diff --git a/include/linux/usb/quirks.h b/include/linux/usb/quirks.h index eeb7c2157c72..8fbcca4432bf 100644 --- a/include/linux/usb/quirks.h +++ b/include/linux/usb/quirks.h @@ -72,4 +72,9 @@ /* device has endpoints that should be ignored */ #define USB_QUIRK_ENDPOINT_IGNORE BIT(15) =20 +/* + * Limits the bInterval value to 9 instead of default value 16 + */ +#define USB_QUIRK_REDUCE_FRAME_INTR_BINTERVAL BIT(16) + #endif /* __LINUX_USB_QUIRKS_H */ --=20 2.17.1