From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A5DC22253EE for ; Thu, 20 Aug 2026 08:21:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.17 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787214109; cv=none; b=JXlJ7D1bVBR67dhdwrb4u04mtXK2UbMWw6SSLpa2x7Rep6syyDgQixEVPzL9vRUpQSsL3Q82RLNmcXhYRcG8t+8JxwrufrdO0WUArFKw52jM60KPlL2TGQQRCXjijBGGI2j9aMYXh5A2XYmRsRn/foEugr9PZrT0YQmYKx9hlzo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787214109; c=relaxed/simple; bh=hU6WbeKXjkf04ex0lb3C0wtWXl/i8eF6gaU6bGhNuCE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Lf8dzET1IS8RZ1Xfc6Eafkm2b+rFbcCJJ6M9POj1XRGaBBPfZlCne5+3xhxgHO9C56IsID9Fw6kKomTP3cotkaKx7BuIEcgdHbu82anSgrb1GzjZiUHhRvl6YWuK9kLC3JE+tn/WV1DdcQCo3zuwtumQH5D5Ml0YvtMTN5QtKhM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=lxpFUJNJ; arc=none smtp.client-ip=198.175.65.17 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="lxpFUJNJ" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1787214107; x=1818750107; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=hU6WbeKXjkf04ex0lb3C0wtWXl/i8eF6gaU6bGhNuCE=; b=lxpFUJNJ1daLpGSwOpvy4xyBswHldLybpcEIuZWSqOlVn8SeR3FYQSqS KR55BM+2m6bi1VVfH9ClGpdivfYzmNrpvTqyZgB8GYsyaiScn2F3eMCL3 BQdBKc6WRD4X+EOvJ5ng+hW8yifTSfkJ3a50majuJEyWeh9UWD4M530HK SwRK+JlV6ty1oKajaGfLbkNnHvlsSLChLN2ZocTzXZ6nAVcRlUegYEaRi xuU7JrIfaq4VK71wiza1EkhjMNZfaSAPiSrcSA6uUzdwHQZVnQxjCok0K 0P2xZrBUdTUSZXWpPpPQM+HVDZOr4NjFUD+h8M9rLgiwknQMnGVkZIQh7 Q==; X-CSE-ConnectionGUID: LnGBOh2ASpGhQHWzbWAWCQ== X-CSE-MsgGUID: AWW2FdToS+OI4m1JPkVNYg== X-IronPort-AV: E=McAfee;i="6800,10657,11880"; a="87756512" X-IronPort-AV: E=Sophos;i="6.25,232,1779174000"; d="scan'208";a="87756512" Received: from fmviesa003.fm.intel.com ([10.60.135.143]) by orvoesa109.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Aug 2026 01:21:47 -0700 X-CSE-ConnectionGUID: u4KLPAvpQsSFN31p1v9Wdw== X-CSE-MsgGUID: 630S6q5bSiCvUmRf6g6HxA== X-ExtLoop1: 1 Received: from amilburn-desk.amilburn-desk (HELO [10.245.245.28]) ([10.245.245.28]) by fmviesa003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Aug 2026 01:21:46 -0700 Message-ID: Date: Thu, 20 Aug 2026 11:21:24 +0300 Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [BUG] xhci: repeated URB cancel on UVC status interrupt EP (0x83) loops for ~15s, stalls camera - Intel Cannon Point-LP [8086:9ded] To: Michal Pecio , =?UTF-8?B?0JTQvNC40YLRgNC40Lk=?= Cc: "linux-usb@vger.kernel.org" References: <1551785954451@mail.yandex.ru> <20260815215259.014cc324.michal.pecio@gmail.com> <20260818000909.31af0ae3.michal.pecio@gmail.com> <358afe43-5f0f-41f6-89cc-129b20ef7641@yandex.ru> <20260818232945.2c67b15b.michal.pecio@gmail.com> Content-Language: en-US From: Mathias Nyman In-Reply-To: <20260818232945.2c67b15b.michal.pecio@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 8/19/26 00:29, Michal Pecio wrote: > On Tue, 18 Aug 2026 20:31:17 +0300, Дмитрий wrote: >> Hi Michal, >> >> I tested the suggested commit: >> >> 3d9eeb336131bc5a174367c384fa00c15c8744fd >> >> on top of Fedora kernel 7.1.8 with the earlier commit >> 7c0c31c66a7f9daace156bac427aafb2f4bbb5fc also applied. >> >> The resulting kernel was: >> >> 7.1.8-200.xhci3d9eeb3.fc44.x86_64 >> >> COPR build: >> >> https://copr.fedorainfracloud.org/coprs/vertigo-red/kernel-xhci-deq/build/10875339/ >> >> IOMMU remained enabled in translated, strict mode: >> >> intel_iommu=on iommu.passthrough=0 iommu.strict=1 >> >> There were no DMAR or IOMMU faults. >> >> A journal-cursor-bounded run with dynamic debug enabled for >> drivers/usb/host/xhci-ring.c timed out after 45.026 seconds: >> >> rc=124 >> >> The v4l2-ctl output contained 22 capture markers and reported 239 >> dropped buffers. During the exact test interval, the kernel logged: Is the camera still unusable with this new kernel if you disable all debugging? With the "All TDs skipped" issue fixed the driver should now be in sync with the isoch ring. > > This number of Missed Service Errors is excessive and may be the main > reason for data loss. Unfortunately, I don't konw what causes it. Some > users reported seeing correlation with CPU load (it may go both ways - > either high or low CPU load causes errors). > > It notably shouldn't be affected by scheduling patches in usb-next, > because uvcvideo uses URB_ISO_ASAP. And you say the bug is very old. > > Maybe it's something to do with multi-TRB TDs? Would it get any better > in video modes that don't produce "spurious events"? > Could you take a short xhci trace of this issue? It should show the content of those TRBs in mode detail. TRB fields like TD size are more important in Multi-TRB TDs. Controller uses those for scheduling. mount -t debugfs none /sys/kernel/debug echo 81920 > /sys/kernel/debug/tracing/buffer_size_kb echo 1 > /sys/kernel/debug/tracing/events/xhci-hcd/enable echo 1 > /sys/kernel/debug/tracing/tracing_on < Reproduce issue > Send content of /sys/kernel/debug/tracing/trace Content of HCCPARAMS2 register and USBCMD register would also be useful as those dictate how the TRB fields are interpreted. cat /sys/kernel/debug/usb/xhci/0000:00:14.0/reg-cap cat /sys/kernel/debug/usb/xhci/0000:00:14.0/reg-op Thanks Mathias