From owner-freebsd-arm@freebsd.org Tue Oct 27 08:03:11 2020 Return-Path: Delivered-To: freebsd-arm@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 1E174441EED for ; Tue, 27 Oct 2020 08:03:11 +0000 (UTC) (envelope-from hps@selasky.org) Received: from mail.turbocat.net (turbocat.net [IPv6:2a01:4f8:c17:6c4b::2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4CL42Q2FMTz4SrJ for ; Tue, 27 Oct 2020 08:03:09 +0000 (UTC) (envelope-from hps@selasky.org) Received: from hps2020.home.selasky.org (unknown [178.17.145.105]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mail.turbocat.net (Postfix) with ESMTPSA id E2FCF260989; Tue, 27 Oct 2020 09:03:01 +0100 (CET) Subject: Re: A RPi4 xHCI VL805 problem that needs to be avoided: "xhci: quirks: add link TRB quirk for VL805" To: Mark Millard , freebsd-arm References: From: Hans Petter Selasky Message-ID: <0b70dbc4-f118-29bc-d814-8fc0a5669382@selasky.org> Date: Tue, 27 Oct 2020 09:02:59 +0100 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 4CL42Q2FMTz4SrJ X-Spamd-Bar: -- Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=pass (mx1.freebsd.org: domain of hps@selasky.org designates 2a01:4f8:c17:6c4b::2 as permitted sender) smtp.mailfrom=hps@selasky.org X-Spamd-Result: default: False [-2.89 / 15.00]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; RCVD_TLS_ALL(0.00)[]; FROM_HAS_DN(0.00)[]; R_SPF_ALLOW(-0.20)[+a:mail.turbocat.net:c]; MID_RHS_MATCH_FROM(0.00)[]; MIME_GOOD(-0.10)[text/plain]; DMARC_NA(0.00)[selasky.org]; NEURAL_HAM_LONG(-1.02)[-1.024]; TO_MATCH_ENVRCPT_SOME(0.00)[]; TO_DN_ALL(0.00)[]; NEURAL_HAM_SHORT(-0.49)[-0.490]; RCPT_COUNT_TWO(0.00)[2]; NEURAL_HAM_MEDIUM(-1.07)[-1.072]; FREEMAIL_TO(0.00)[yahoo.com,freebsd.org]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:24940, ipnet:2a01:4f8::/29, country:DE]; RCVD_COUNT_TWO(0.00)[2]; MAILMAN_DEST(0.00)[freebsd-arm] X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 27 Oct 2020 08:03:11 -0000 On 2020-10-27 00:58, Mark Millard via freebsd-arm wrote: > https://github.com/raspberrypi/linux/pull/3929 reports: > > QUOTE > The VL805 controller can't cope with the TR Dequeue Pointer for an endpoint > being set to a Link TRB. The hardware-maintained endpoint context ends up > stuck at the address of the Link TRB, leading to erroneous ring expansion > events whenever the enqueue pointer wraps to the dequeue position. > > If the search for the end of the current TD and ring cycle state lands on > a Link TRB, move to the next segment. > END QUOTE > > Also: Dealing with the link trb also toggling the ring cycle state > is something to watch for according to the later notes. > Is this an issue under FreeBSD too? Can it be reproduced? --HPS