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{ "id": 2220760, "url": "http://patchwork.ozlabs.org/api/1.1/covers/2220760/?format=api", "web_url": "http://patchwork.ozlabs.org/project/ubuntu-kernel/cover/20260408002809.232479-1-acelan.kao@canonical.com/", "project": { "id": 15, "url": "http://patchwork.ozlabs.org/api/1.1/projects/15/?format=api", "name": "Ubuntu Kernel", "link_name": "ubuntu-kernel", "list_id": "kernel-team.lists.ubuntu.com", "list_email": "kernel-team@lists.ubuntu.com", "web_url": null, "scm_url": null, "webscm_url": null }, "msgid": "<20260408002809.232479-1-acelan.kao@canonical.com>", "date": "2026-04-08T00:28:08", "name": "[SRU,R,0/1] Bluetooth device (MT7925) not detected on USB bus with linux-oem-6.17", "submitter": { "id": 2976, "url": "http://patchwork.ozlabs.org/api/1.1/people/2976/?format=api", "name": "AceLan Kao", "email": "acelan.kao@canonical.com" }, "mbox": "http://patchwork.ozlabs.org/project/ubuntu-kernel/cover/20260408002809.232479-1-acelan.kao@canonical.com/mbox/", "series": [ { "id": 499052, "url": "http://patchwork.ozlabs.org/api/1.1/series/499052/?format=api", "web_url": "http://patchwork.ozlabs.org/project/ubuntu-kernel/list/?series=499052", "date": "2026-04-08T00:28:08", "name": "Bluetooth device (MT7925) not detected on USB bus with linux-oem-6.17", "version": 1, "mbox": "http://patchwork.ozlabs.org/series/499052/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/covers/2220760/comments/", "headers": { "Return-Path": "<kernel-team-bounces@lists.ubuntu.com>", "X-Original-To": "incoming@patchwork.ozlabs.org", "Delivered-To": "patchwork-incoming@legolas.ozlabs.org", "Authentication-Results": [ "legolas.ozlabs.org;\n\tdkim=fail reason=\"signature verification failed\" (2048-bit key;\n unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256\n header.s=20251104 header.b=DMFofi9I;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=lists.ubuntu.com\n (client-ip=185.125.189.65; helo=lists.ubuntu.com;\n envelope-from=kernel-team-bounces@lists.ubuntu.com;\n receiver=patchwork.ozlabs.org)" ], "Received": [ "from lists.ubuntu.com (lists.ubuntu.com [185.125.189.65])\n\t(using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4fr3nh3PxMz1yD3\n\tfor <incoming@patchwork.ozlabs.org>; Wed, 08 Apr 2026 10:28:24 +1000 (AEST)", "from localhost ([127.0.0.1] helo=lists.ubuntu.com)\n\tby lists.ubuntu.com with esmtp (Exim 4.86_2)\n\t(envelope-from <kernel-team-bounces@lists.ubuntu.com>)\n\tid 1wAGmG-0005BB-7l; Wed, 08 Apr 2026 00:28:16 +0000", "from mail-qv1-f51.google.com ([209.85.219.51])\n by lists.ubuntu.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128)\n (Exim 4.86_2) (envelope-from <acelan@gmail.com>) id 1wAGmF-0005Aq-5H\n for kernel-team@lists.ubuntu.com; Wed, 08 Apr 2026 00:28:15 +0000", "by mail-qv1-f51.google.com with SMTP id\n 6a1803df08f44-8a05c388b27so108767766d6.3\n for <kernel-team@lists.ubuntu.com>; Tue, 07 Apr 2026 17:28:14 -0700 (PDT)", "from localhost (211-75-139-220.hinet-ip.hinet.net. [211.75.139.220])\n by smtp.gmail.com with ESMTPSA id\n 6a1803df08f44-8a593bf4b0fsm163239516d6.15.2026.04.07.17.28.11\n for <kernel-team@lists.ubuntu.com>\n (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256);\n Tue, 07 Apr 2026 17:28:12 -0700 (PDT)" ], "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/relaxed;\n d=gmail.com; s=20251104; t=1775608093; x=1776212893; darn=lists.ubuntu.com;\n h=content-transfer-encoding:mime-version:message-id:date:subject:to\n :from:sender:from:to:cc:subject:date:message-id:reply-to;\n bh=6coqjb+0oVXALkxlJGVarRRGB1UAKKGhnay+cAGg9fI=;\n b=DMFofi9IpkO8yBYeCd/hzvl9+4o9Lt+Y+sphoZZ+qlPj/K/GrAPiNbmvAMfJJMziCP\n 0OMvuGuADa8jSIlz+k1nDxKLSaOl51E5Vy/+QFVKyz5A7zc8sFpRuYzdAkQymrXqUBhm\n dvifq/a4MJge33jnXYG8b9AQs59GkdogKAgPtgDXHfXfXXBlikQim4tswbUsdqzDZ6w0\n GcH0Xz1R6VNWRHNgnz0bGRuCiiDMTX8hN8znuvRlmNy2d4r/T7dbMjEZJtjyDLqU3RU/\n qTxmPOvncqVGeSUoVXPIjmqw7T54mnH6QO/+r2Q+MzYZSTPm2mPXh7mWzn+eA9fbBtWa\n cFqw==", "X-Google-DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/relaxed;\n d=1e100.net; s=20251104; t=1775608093; x=1776212893;\n h=content-transfer-encoding:mime-version:message-id:date:subject:to\n :from:sender:x-gm-gg:x-gm-message-state:from:to:cc:subject:date\n :message-id:reply-to;\n bh=6coqjb+0oVXALkxlJGVarRRGB1UAKKGhnay+cAGg9fI=;\n b=fZC7qkCiBGkqb1jM4TvxpjsTPLDLDFpuT6YfSDpEH5jJC8Zao4XPK2MQVmntSYdjP/\n phk1lVLNcTAUirjt/ZthxgqSHoLIyObylympz/riu6oZeAOiHipAa/xzAFjBNHzSQ3X3\n 1FlUg6HGCKlh03nn5Dhns5u0dpVpkXVSg83o29MAPczokX+YbLY2n58r29MaJhKSLb9t\n YQAppMnioKvTy7NlxGJzU1N6L97fv4hi4Dd+txQlmZ2v5nhIuc5lxiPpMntSId+CYXJ0\n 3sGt1FQG5vTTHqGsaUuTNptNk02x33iul6okUNvBmH4QDj/PH8kh48PZOpF1reXioEHQ\n iRsQ==", "X-Gm-Message-State": "AOJu0YyDkF1nE76Y3JAI3wasGo+pwcvf3uUrFsSjpSxx+sg+T6ZKJ0DW\n zVs/l8P4ymASTQ/cBadaJvTPBFw+5BBtrxn66xDOLudjNLkUYmLOzFcSuap+xSGc", "X-Gm-Gg": "AeBDietirnUoceAjTePTAmvJ2TSMbx2QT4S3oypmjyU41WfskxX3LKiLAwftyWQZ3hw\n ciL2Kfio5H6FMvjE/KjmFYfStPha3F2xe43ixKavpaJ4TMubKCELxp9md/Kl6nH5AikLPlIHdF7\n UOrje2ehTBso4WnTrqcbeLVFk3ZQfyes95HMpbiRRF3hZg7/8vJaS54ZqDtz/JOAAyKgrRLiQ84\n jz406cF7V3g5VhqbTFSRueJORp3i3DD1e2c/TvenRNi340Ma9/MNiHjMi1UCYA27EjM/EF4XhfB\n Yl4JamVa42zF4hepEcu9zinmr0rqgahWcJtF6xQdYAWysgBPkPTMnrscscpkSidbxo3P/WcTFGR\n 5uGFazzRX4RI4iHgXF4CB5Bi6/S4TPnZ62dI0wTtF9UBxcmJZVTaAeBfV1XfV9dt1pTe5LkW3oZ\n 9bL/vq5q/ORU46HBbZn7KdaOIYLSuqMV8FCKab/mfCnkLDWEBxAHtD", "X-Received": "by 2002:a05:6214:4186:b0:899:efbf:9292 with SMTP id\n 6a1803df08f44-8a7046de190mr329931486d6.43.1775608093365;\n Tue, 07 Apr 2026 17:28:13 -0700 (PDT)", "From": "AceLan Kao <acelan.kao@canonical.com>", "To": "kernel-team@lists.ubuntu.com", "Subject": "[SRU][R][PATCH 0/1] Bluetooth device (MT7925) not detected on USB bus\n with linux-oem-6.17", "Date": "Wed, 8 Apr 2026 08:28:08 +0800", "Message-ID": "<20260408002809.232479-1-acelan.kao@canonical.com>", "X-Mailer": "git-send-email 2.53.0", "MIME-Version": "1.0", "Received-SPF": "pass client-ip=209.85.219.51; envelope-from=acelan@gmail.com;\n helo=mail-qv1-f51.google.com", "X-BeenThere": "kernel-team@lists.ubuntu.com", "X-Mailman-Version": "2.1.20", "Precedence": "list", "List-Id": "Kernel team discussions <kernel-team.lists.ubuntu.com>", "List-Unsubscribe": "<https://lists.ubuntu.com/mailman/options/kernel-team>,\n <mailto:kernel-team-request@lists.ubuntu.com?subject=unsubscribe>", "List-Archive": "<https://lists.ubuntu.com/archives/kernel-team>", "List-Post": "<mailto:kernel-team@lists.ubuntu.com>", "List-Help": "<mailto:kernel-team-request@lists.ubuntu.com?subject=help>", "List-Subscribe": "<https://lists.ubuntu.com/mailman/listinfo/kernel-team>,\n <mailto:kernel-team-request@lists.ubuntu.com?subject=subscribe>", "Content-Type": "text/plain; charset=\"utf-8\"", "Content-Transfer-Encoding": "base64", "Errors-To": "kernel-team-bounces@lists.ubuntu.com", "Sender": "\"kernel-team\" <kernel-team-bounces@lists.ubuntu.com>" }, "content": "From: \"Chia-Lin Kao (AceLan)\" <acelan.kao@canonical.com>\n\nBugLink: https://bugs.launchpad.net/bugs/2145164\n\n[Impact]\nMT7925 Bluetooth on Dell systems fails to enumerate at boot when the\nBT_RST GPIO is stuck low. The device never comes up and Bluetooth is\nunavailable. The only recovery is a full mechanical power-off (G3 cycle).\n\nError log:\n[ 6.813942] usb 3-10: device descriptor read/64, error -110\n[ 22.685978] usb 3-10: device descriptor read/64, error -110\n[ 28.317963] usb 3-10: device descriptor read/64, error -110\n[ 44.189949] usb 3-10: device descriptor read/64, error -110\n[ 44.189960] usb usb3-port10: unable to enumerate USB device\n\nWarm reboots and S5 sleep do not clear the stuck GPIO state. Hits 100%\non affected hardware once the GPIO is stuck.\n\n[Fix]\nAdd usb_acpi_port_prr_reset() to drivers/usb/core/usb-acpi.c. When a\nUSB port has an ACPI _PRR method, the function calls _RST on the\nreturned power resource to toggle the hardware reset line.\n\nWire it into hub_port_connect() during the mid-retry VBUS power-cycle:\ncall _PRR._RST while VBUS is off so the GPIO pulse completes before the\ndevice gets power. After VBUS comes back on, sleep 100 ms (per USB 2.0\nspec §7.1.7.3 Fig. 7-29) when _RST succeeded, because\nhub_power_on_good_delay() has no minimum floor and can return as little\nas 20 ms on xHCI root hubs.\n\nhttps://lore.kernel.org/lkml/20260326011708.1128840-1-acelan.kao@canonical.com/T/#u\n\n[Test Plan]\nTrigger the stuck-GPIO condition (G3 cycle on affected Dell hardware to\nput the system in a normal state, then warm reboot to reproduce).\n\nWithout patch:\n- dmesg shows repeated \"device descriptor read/64, error -110\"\n- Bluetooth unavailable; recovery requires G3 cycle\n\nWith patch:\n- dmesg shows \"attempt power cycle\" followed by successful enumeration\n- Bluetooth comes up without any manual intervention\n\nExpected dmesg with patch:\n[ 44.294065] usb usb3-port10: attempt power cycle\n[ 44.872709] usb 3-10: new high-speed USB device number 6 using xhci_hcd\n[ 44.888293] usb 3-10: New USB device found, idVendor=0489, idProduct=e139, bcdDevice= 1.00\n[ 44.888318] usb 3-10: Manufacturer: MediaTek Inc.\n\n[Where problems could occur]\nCould affect USB hub port handling in drivers/usb/core/hub.c and\nusb-acpi.c.\n\nusb_acpi_port_prr_reset() is a no-op on ports with no ACPI _PRR method,\nso non-affected hardware should be unaffected. If the ACPI method\nevaluation returns an unexpected object type or the _RST call hangs, the\nhub_port_connect() retry loop could stall or log spurious errors.\n\nThe 100 ms sleep is conditional on _RST succeeding (prr_reset == 0), so\nit does not add latency to ports without _PRR.\n\nChia-Lin Kao (AceLan) (1):\n UBUNTU: SAUCE: USB: hub: call ACPI _PRR reset during port power-cycle\n on enumeration failure\n\n drivers/usb/core/hub.c | 14 ++++++++\n drivers/usb/core/usb-acpi.c | 68 +++++++++++++++++++++++++++++++++++++\n drivers/usb/core/usb.h | 3 ++\n 3 files changed, 85 insertions(+)" }