From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f181.google.com (mail-pl1-f181.google.com [209.85.214.181]) (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 C2EAD19E839 for ; Tue, 28 Jul 2026 19:52:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.181 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785268334; cv=none; b=sVyZwTdqAZstjAsPHHBaU1qE/7ATyKFQn09b8/fqeSDWknjKbfZNQwO3P5uGthrXMhRyAa3fORRaW/j/3GsNwOQQPc8qQy30bD3N6h07OO3idTUYjJuZZ836CKkoZ7vN7JQlYiGglXvmsCZmBJooYja1ixP1SIgGCL8a4PWP4bM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785268334; c=relaxed/simple; bh=Nj8Uu4X/8wvVYZY4l0Sd8MNETHKyAv52T2oSotFNfRQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CB/mplM2Xx6bhe6RUHACpzytrJLH5bONudhkEIpBOudxN6RG0YTB5U4hkRD0ORU1HRQ3UcOJkOjjiH7nVlCyy8zfl7G8EPyMGkLLm/j9l4xP6TWZypRHTiLDLc1EVxiD6vanLbmCNvxnA/5W41TZo5D8Tayg0bBl0cEiZU+4+6k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=gkd4pSvp; arc=none smtp.client-ip=209.85.214.181 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="gkd4pSvp" Received: by mail-pl1-f181.google.com with SMTP id d9443c01a7336-2cce6a0c9c3so3574695ad.1 for ; Tue, 28 Jul 2026 12:52:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1785268332; x=1785873132; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=NLQ5jvybCf/zGwa1IealBNI//5/h9wcvMKi+jtTkRd4=; b=gkd4pSvpCaC1gGxUiGgtCx9OHV9ypJ48wjAk6aInZqJYQQ8JC2GU2wx86OoGmfQr6Q x/quCLMGvtxOxrgpN2qTEgTi9ff93p0Ffi2pla4OvtDZQmKiJ6+gJuKvNMstXkK/hJ03 Q2VgS5fHgkdw/OPfDOaBUEZcyBV2nJMlEkHkEFQe+v+q6xHstJkXph8ogunFftvWUFsJ 03KixhpEGk2o239GT6aZzFnE3dKGeJ6wr2Q6+NLxLSNmnDULQIn27wRoJBgk/l+5iQuU hXg/m4weLcLAjf9AawecEPWnzIB7o+cqDyyIwlQej2rdJT7XWo2yyWn5EDVCNPMRln/m HCOQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1785268332; x=1785873132; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=NLQ5jvybCf/zGwa1IealBNI//5/h9wcvMKi+jtTkRd4=; b=b9T3tywTl+y4CBzXTP3iwf+ZmeG57rfiHwVOhwVbDhuBiJxaboreKwj2jll1FK+cJ5 ea0z/e/z/eVWrc644ktU9E0lE3gKCIZQl0gpqtorD/a981jMHgixByXqC0xR4Uu9kZzO UJPHnZ7SLTyt+HOPrRX/GBURhcM2XveR8RSumTcwlEcP0Itk48AbKNxRnCE3HIPV11hy UJbXH++XVP7rMKMb8PfSx6nzBCNGIYL6JHyzl+gdZX8l7z0tLSepS/IddquOEaW4g3p4 EzeMOpzEZWd0fx7uRj9aaTvx90iapatnvfjW/YveDPzyeqbY+DKc4P5T/YMJvSUo5+FP pGbQ== X-Forwarded-Encrypted: i=1; AHgh+RrwDD+Fs/OPDjS6Qwh35a05zBznwaakeGJkiLKZkuPjS6+aaaLXVm+2lXxNgT9jvPlRWJF82WBcNxs=@vger.kernel.org X-Gm-Message-State: AOJu0Yy0kNnTWWk1sZAOguvZ7lfZG01isUQo2xSAiN4u+dSqXZ4tnAMo P0jmislbucLhDf8gQlyggWS1qbw9O2KUUNFjMKu3r6fQBGH3M1CJnjyqySkah250 X-Gm-Gg: AR+sD11aDIx41Z7I2T5n0tsjI32Kd3tTaAEYHKkvmAKLHd3AqoC+IYbhPrqcNrK/FXH K7ldZp6vuv7iScPiBrfSVWAC6aoLM8X51YtqAS3nsTCx0a/W67I/f0nNjkdY/6OELFluG13y+oD WBrgEAp3OQ86Ui3o6tkHnmPrBRfH4P1XcK+etf7E5avDxvym/ibDcaj7F3Djx9y3UkFTfrJunf1 P8S1dXNt/jZ0w2+GIlGmGHHhTJd0YaxUA7RnDLvfi81x11CcEt6ybZyD0R1M4xdrw88xfRrsMl4 uGzRR8ITbCodl5YXB6kBy+wv3UP/RSBkYqwMF7yq56ZR76KTRnAksTaC3gBQ8lJNEOq4Jp2/3MS f/M7X9YzwCiEmcnTT985FyLGVmx8tmmO1+bpA2S55rDNSCDlSrdX+mNfNIst53NwGK4yEfS2zG9 /fkFiwrx6XDY9OWH68hjkvF1kmd1Uc/WgPq7IT0gJFKj7X11SVAYJUNJNHOYEOuMdnTz0QoyCZd HsrqUhnJ/KmdD6M8q+qpJGlFmTDr4U22CRdRBC7FlyHvY1HRkQe7A== X-Received: by 2002:a17:903:2ca:b0:2c6:9f66:d573 with SMTP id d9443c01a7336-2d015acd4c1mr45653945ad.2.1785268332085; Tue, 28 Jul 2026 12:52:12 -0700 (PDT) Received: from localhost ([103.170.252.6]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-31504d480c5sm2525348eec.25.2026.07.28.12.52.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Jul 2026 12:52:11 -0700 (PDT) From: Nikhil Solanke To: linux-usb@vger.kernel.org Cc: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, stern@rowland.harvard.edu, michal.pecio@gmail.com, corbet@lwn.net, skhan@linuxfoundation.org, stable@vger.kernel.org, linux-doc@vger.kernel.org, ishaan.dandekar@gmail.com, Nikhil Solanke Subject: [PATCH v5 1/2] usb: core: Add quirk for 255-bytes initial config read Date: Wed, 29 Jul 2026 01:21:57 +0530 Message-ID: <20260728195158.65162-2-nikhilsolanke5@gmail.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260728195158.65162-1-nikhilsolanke5@gmail.com> References: <20260728195158.65162-1-nikhilsolanke5@gmail.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Certain third-party USB game controllers exposing (or spoofing) an Xbox 360-compatible interface (VID:PID 045e:028e) fail to enumerate under Linux. The device disconnects from the bus without responding to the initial GET_DESCRIPTOR(CONFIGURATION) request, and the kernel logs 'unable to read config index 0 descriptor/start: -71'. The device then falls back to a secondary Android HID mode (with a different VID:PID), losing XInput functionality including rumble support. The failure reproduces across multiple machines, host controller types, and kernel versions including current mainline and LTS. The device enumerates correctly and remains in XInput mode under Windows. Notably, the device enumerates correctly in Android mode when the same 9-byte request is issued for that mode's configuration descriptor, confirming the firmware bug is specific to the XInput mode. usbmon traces from Linux and Wireshark/USBPcap traces from Windows are identical up to the point of failure, with no visible protocol-level difference explaining the divergence. The root cause was identified when Michal Pecio discovered via a QEMU bus-level capture that Windows does not use wLength=9 for the initial config descriptor request; it uses wLength=255. Alan Stern subsequently confirmed this with a bus analyzer on a different USB 2.0 device, and Michal verified the behavior goes back to Windows 95 OSR2.1. So, add a new quirk flag USB_QUIRK_WINDOWS_CONFIG_REQ_SIZE which causes usb_get_configuration() to issue a 255 byte sized configuration request instead of USB_DT_CONFIG_SIZE (9) for the initial GET_DESCRIPTOR(CONFIGURATION) request, mimicking long-standing Windows behavior. This patch intentionally does not add any new VID:PID entries using this quirk. Some affected Xbox 360-compatible controllers spoof Microsoft's VID:PID, while genuine Microsoft controllers already enumerate correctly and do not require this quirk. Other affected clone devices use their own VID:PID pairs and can be added individually as they are identified. Suggested-by: Alan Stern Suggested-by: Michal Pecio Closes: https://lore.kernel.org/linux-usb/CAFgddh+JWdT4LLwMc5qjM8q_pBu-fRo2qADR5ovAKoGHWMQrRw@mail.gmail.com/ Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Acked-by: Alan Stern Signed-off-by: Nikhil Solanke --- .../admin-guide/kernel-parameters.txt | 5 +++ drivers/usb/core/config.c | 32 ++++++++++++++----- drivers/usb/core/quirks.c | 4 +++ include/linux/usb/quirks.h | 3 ++ 4 files changed, 36 insertions(+), 8 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index b5493a7f8f22..3d35270dddef 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -8169,6 +8169,11 @@ Kernel parameters q = USB_QUIRK_FORCE_ONE_CONFIG (Device claims zero configurations, forcing to 1); + r = USB_QUIRK_WINDOWS_CONFIG_REQ_SIZE (Device + fails during initialization when asked for + 9-bytes configuration descriptor request. + Ask for 255-bytes request instead to mirror + Windows' behavior); Example: quirks=0781:5580:bk,0a5c:5834:gij usbhid.mousepoll= diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c index 45e20c6d76c0..346a2faa9bb8 100644 --- a/drivers/usb/core/config.c +++ b/drivers/usb/core/config.c @@ -912,6 +912,18 @@ int usb_get_configuration(struct usb_device *dev) unsigned char *bigbuffer; struct usb_config_descriptor *desc; int result; + size_t usb_config_req_size; + + /* + * We usually start by grabbing the first 9-bytes descriptor so we know + * how long the whole configuration is. Some devices with quirky + * firmware will fail enumeration, so if the quirk is set, use 255 instead, + * mirroring the behavior of Windows. + */ + if (dev->quirks & USB_QUIRK_WINDOWS_CONFIG_REQ_SIZE) + usb_config_req_size = 255; + else + usb_config_req_size = USB_DT_CONFIG_SIZE; if (ncfg > USB_MAXCONFIG) { dev_notice(ddev, "too many configurations: %d, " @@ -938,15 +950,13 @@ int usb_get_configuration(struct usb_device *dev) if (!dev->rawdescriptors) return -ENOMEM; - desc = kmalloc(USB_DT_CONFIG_SIZE, GFP_KERNEL); + desc = kmalloc(usb_config_req_size, GFP_KERNEL); if (!desc) return -ENOMEM; for (cfgno = 0; cfgno < ncfg; cfgno++) { - /* We grab just the first descriptor so we know how long - * the whole configuration is */ result = usb_get_descriptor(dev, USB_DT_CONFIG, cfgno, - desc, USB_DT_CONFIG_SIZE); + desc, usb_config_req_size); if (result < 0) { dev_err(ddev, "unable to read config index %d " "descriptor/%s: %d\n", cfgno, "start", result); @@ -956,16 +966,14 @@ int usb_get_configuration(struct usb_device *dev) dev->descriptor.bNumConfigurations = cfgno; break; } else if (result < 4) { - dev_err(ddev, "config index %d descriptor too short " - "(expected %i, got %i)\n", cfgno, - USB_DT_CONFIG_SIZE, result); + dev_err(ddev, "config index %d descriptor too short (asked for %zu, got %i)\n", + cfgno, usb_config_req_size, result); result = -EINVAL; goto err; } length = max_t(int, le16_to_cpu(desc->wTotalLength), USB_DT_CONFIG_SIZE); - /* Now that we know the length, get the whole thing */ bigbuffer = kmalloc(length, GFP_KERNEL); if (!bigbuffer) { result = -ENOMEM; @@ -975,6 +983,13 @@ int usb_get_configuration(struct usb_device *dev) if (dev->quirks & USB_QUIRK_DELAY_INIT) msleep(200); + /* Skip the second read if we already got everything */ + if (result >= length) { + memcpy(bigbuffer, desc, length); + goto store_and_parse; + } + + /* Get the whole thing */ result = usb_get_descriptor(dev, USB_DT_CONFIG, cfgno, bigbuffer, length); if (result < 0) { @@ -989,6 +1004,7 @@ int usb_get_configuration(struct usb_device *dev) length = result; } +store_and_parse: dev->rawdescriptors[cfgno] = bigbuffer; result = usb_parse_configuration(dev, cfgno, diff --git a/drivers/usb/core/quirks.c b/drivers/usb/core/quirks.c index 87ee2d938bc0..f5a60ccf21d3 100644 --- a/drivers/usb/core/quirks.c +++ b/drivers/usb/core/quirks.c @@ -142,6 +142,10 @@ static int quirks_param_set(const char *value, const struct kernel_param *kp) break; case 'q': flags |= USB_QUIRK_FORCE_ONE_CONFIG; + break; + case 'r': + flags |= USB_QUIRK_WINDOWS_CONFIG_REQ_SIZE; + break; /* Ignore unrecognized flag characters */ } } diff --git a/include/linux/usb/quirks.h b/include/linux/usb/quirks.h index b3cc7beab4a3..a4043b33c2c2 100644 --- a/include/linux/usb/quirks.h +++ b/include/linux/usb/quirks.h @@ -81,4 +81,7 @@ /* Device claims zero configurations, forcing to 1 */ #define USB_QUIRK_FORCE_ONE_CONFIG BIT(18) +/* Use a 255 bytes config descriptor request mirroring windows behavior */ +#define USB_QUIRK_WINDOWS_CONFIG_REQ_SIZE BIT(19) + #endif /* __LINUX_USB_QUIRKS_H */ -- 2.54.0