From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=52.129.46.36 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793226495; b=jJd0bb+ZraDlp6j/lXfyed1+cN999rkKczqQtZv90OduZIEBRAuMBOhvMPhZH8UNbXhg mjDQLaAny2rV2fJAw9kWFl7R+uYQA33eFkXurRdb11wgFsHHdOyA5GMF38uMmQutQibsb Y7mJxlZjz4a9jYcSkZr0AWcEyBANubb9XMNzpCEm4NB5cZMW3gnQ36i3f7smsBgIfakRr +HYUGkmqBsE9Aopk6JNH1osY4YyVvgYFoxJx+IlnN+M186hWjEVBOdzeEdhrraEqNCyvs 4lhOQONUZbi9Rs6o2gXQfg+jLxdRNjEfri/atNZF7gTFNzYQI0sUtim/viKExZA1u0A== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793226495; h=DMARC-Filter:Received:DKIM-Signature:From:To:Cc:Subject:Date: Message-Id:X-Mailer:MIME-Version:Content-Transfer-Encoding; bh=c9nNxsHjKnfDkOrla0IRUfyl7eVn4AD2MQVhH0+zpkw=; b=SOQbSD1UzAVQpWQh9QtwFwYNPnkVG/DQyb+DdtAebGV9fm4FVZnck3nVsQRPxk/J3U++ zpkaILMWach+1xFXAxQAudRBHaGbr7TkdxKgb/CuFJxuN81Ch5+sZweCqN+cnEWsSipKs MI3GOMgCYYrcmaP+ejpqCqs3ump9ahlB6x/AT63DjYoFkMLXakoZscHzMWrL2OcD94u41 JJHnEk6eKLDoyNvM572+8ztkkG7pDBFBYHZQYmcRlAHOzm1BwgngeLtu1Bg0Hfrq3SlFp wJAcstt2L12MWdVzD8a7tg9n8+B2G2cKfl7UrIqrjIRre9Dka6bt/oV8k+VDV7tJC/g== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=nwlink.com; spf=pass smtp.mailfrom=nwlink.com; dkim=pass header.d=nwlink.com header.i=@nwlink.com header.a=rsa-sha256 header.s=mail header.b=ASNxUCHO; arc=none smtp.remote-ip=52.129.46.36 Received: from smtp2.iinet.com (smtp2.iinet.com [52.129.46.36]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5493F606A31A for ; Wed, 28 Oct 2026 22:28:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 5493F606A31A Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=nwlink.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=nwlink.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=nwlink.com header.i=@nwlink.com header.a=rsa-sha256 header.s=mail header.b=ASNxUCHO Received: from porter.hsd1.wa.comcast.net (c-98-203-133-45.hsd1.wa.comcast.net [98.203.133.45]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: kaf@nwlink.com) by smtp2.iinet.com (Postfix) with ESMTPSA id 1328BB40242; Wed, 28 Oct 2026 15:28:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nwlink.com; s=mail; t=1793226489; bh=c9nNxsHjKnfDkOrla0IRUfyl7eVn4AD2MQVhH0+zpkw=; h=From:To:Cc:Subject:Date:From; b=ASNxUCHOV4xfLHEiqahxX0OEWBzlagricUqYlk7Uq278N9mGT6ynqoqucahAo4LOW oEG2tVsV/D7HwPMAQpYMOgb8fUJgnLHWI536//hGDAjU5l5mT/mdEaWOLSutoFo8Ra 9dsCnPr14q5uXzV8vdOQBXFlE56V8pSUcsSwanIHPE52mqwI3hUPxoXfz6vfrsbOCs xgGOHz3EWxXrl7VXrjAHK+sMjhS3nIyKCkPRxRJsrw9xHDxCGG+OSz7WUxJA3FVpyL nocd4CU8z6n8Fedjia2HQKL3zKUjHKcMipBN36tWup1H32zPhO5B5bjGalwWlplXLY 0XdyN89dB7x2g== From: Kyle Farrell To: nkapron@google.com, gregkh@linuxfoundation.org Cc: pavel.hofman@ivitera.com, linux-usb@vger.kernel.org, Kyle Farrell Subject: [PATCH] usb: gadget: f_uac2: prevent invalid bInterval auto-selection Date: Wed, 28 Oct 2026 15:28:00 -0700 Message-Id: <20261028222800.782988-1-kaf@nwlink.com> X-Mailer: git-send-email 2.34.1 X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When p_hs_bint or c_hs_bint is 0, the driver selects the largest bInterval from 4 down to 1 for which the required bandwidth fits the maximum packet size. The original implementation intends to keep bInterval at 1 when required bandwidth exceeds the single-packet maximum, but the search loop instead decrements bInterval to 0 in that case. A bInterval of 0 is invalid for an isochronous endpoint. A Linux host reports it and substitutes a default: usb 3-8: ... endpoint 0x1 has an invalid bInterval 0, changing to 7 Stop the search at bInterval=1. Maintain existing clamping of wMaxPacketSize and warning about possible data loss when the required bandwidth cannot be accommodated. Fixes: 355a05dc8367 ("usb: gadget: f_uac2: Optionally determine bInterval for HS and SS") Signed-off-by: Kyle Farrell --- drivers/usb/gadget/function/f_uac2.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/usb/gadget/function/f_uac2.c b/drivers/usb/gadget/function/f_uac2.c index d8cf710085a0..9bd59ea5f7fb 100644 --- a/drivers/usb/gadget/function/f_uac2.c +++ b/drivers/usb/gadget/function/f_uac2.c @@ -728,11 +728,11 @@ static int set_ep_max_packet_size_bint(struct device *dev, const struct f_uac2_o bint = opts_bint; max_size_bw = get_max_bw_for_bint(uac2_opts, bint, 8000, is_playback); } else { - /* checking bInterval from 4 to 1 whether the required bandwidth fits */ - for (bint = 4; bint > 0; --bint) { + /* select the largest bInterval that fits, or 1 if none fit */ + for (bint = 4; ; --bint) { max_size_bw = get_max_bw_for_bint( uac2_opts, bint, 8000, is_playback); - if (max_size_bw <= max_size_ep) + if (max_size_bw <= max_size_ep || bint == 1) break; } } base-commit: bdf12cde30830d46a8ef1ba93986356f1164b4f1 -- 2.34.1