From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 C496E1E32D3 for ; Wed, 5 Nov 2025 20:16:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762373815; cv=none; b=V/42so3P9XM+8hPuOd751OKxyriuWRdIOgzCc5/wvd32BOicpjZewKiv4T89lVOboXZkapwBWMO0oguqYXwh6MGVV4laS46aY9EwIchcOD0bdfydrcQ0Wj3vONQviesUWujy0rWL4gJDGHKgGw0RFKe3jPh2cZu6wYv8s1jv+T4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762373815; c=relaxed/simple; bh=GH6a6bz+dzVuiCyuQQDGGa55hsVGdy0pm8h6/IIKXh0=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: Content-Type:MIME-Version; b=SCfmzk3/DZ8L/Pozz6WDRUSdYthYdDMDi2biOb+8TQgMxfrrAawr6jjQsRHTxt8e9IAHVo8XnqFl5V48j3brPSBFg+3QPSYOx1eMufGxCJErPyrKJQ5BpmANQ7I5RAjebeG+1vlEsdKOR56RvddwQYP/QdYYGe1Tt9nJSJ/1iyY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=lZwZB1DT; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="lZwZB1DT" Received: by smtp.kernel.org (Postfix) with ESMTPS id 532AEC19423 for ; Wed, 5 Nov 2025 20:16:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762373815; bh=GH6a6bz+dzVuiCyuQQDGGa55hsVGdy0pm8h6/IIKXh0=; h=From:To:Subject:Date:In-Reply-To:References:From; b=lZwZB1DTLAyL6f5UstOVssvFcgNqkCPjHreGzRMIUudbZlKvCSJWPJbGv0lu3SM+6 3AUVrQ3tpSPrBqE1Pt0P7i/hsiYCMED2f/MpFrHT3q+UnHXj8KfcVZJg0D+2abr/7X mzPeQWgQqT5sRJYTIYdGpZtgSBEczoe17zbDUDZiZQDqzq+3fG+1hJTELFfV+M1xcF ODFkwxk4L6XfCb61CsbK/MYTaqmPUK/xffeNxbiKy/tglwEsABM8ogdQ8c0kKbBUtf b97+MyQNW5LhIr2eQJktzXw1wxl101a0m5OhSotapZs5P3MpqHhWP0aHu1TfFIAN4O 9VvVyVIbMKcDg== Received: by aws-us-west-2-korg-bugzilla-1.web.codeaurora.org (Postfix, from userid 48) id 4D76FC433E1; Wed, 5 Nov 2025 20:16:55 +0000 (UTC) From: bugzilla-daemon@kernel.org To: linux-usb@vger.kernel.org Subject: [Bug 220748] usb: xhci_queue_isoc_tx_prepare ignore start_frame and always assumes URB_ISO_ASAP is set Date: Wed, 05 Nov 2025 20:16:54 +0000 X-Bugzilla-Reason: None X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: AssignedTo drivers_usb@kernel-bugs.kernel.org X-Bugzilla-Product: Drivers X-Bugzilla-Component: USB X-Bugzilla-Version: 2.5 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: stern@rowland.harvard.edu X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: drivers_usb@kernel-bugs.kernel.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugzilla.kernel.org/ Auto-Submitted: auto-generated Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 https://bugzilla.kernel.org/show_bug.cgi?id=3D220748 --- Comment #8 from Alan Stern (stern@rowland.harvard.edu) --- Sorry, yes, urb->interval and urb->start_frame do get modified during submission. Drivers are allowed to read those fields before the URB comple= tes. The documentation from Intel is irrelevant. It discusses the xHCI hardware, but we're talking about the Linux software interface. As for the considerations at the start of this bug report... xhci-hcd is indeed supposed to ignore urb->start_frame during submission and overwrite = it with the actual starting (micro)frame number. And most of the time, xhci-h= cd is supposed to ignore URB_ISO_ASAP. But it's not supposed to ignore URB_ISO_ASAP in cases where the URB was submitted too late. By "too late",= I mean that at the time the URB was submitted, the (micro)frame that it should have been scheduled for -- one period after the last frame of the preceding= URB -- had already elapsed. --=20 You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.=