From owner-freebsd-hackers@freebsd.org Sat Mar 9 21:40:29 2019 Return-Path: Delivered-To: freebsd-hackers@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 52B7B1538274 for ; Sat, 9 Mar 2019 21:40:29 +0000 (UTC) (envelope-from hps@selasky.org) Received: from mail.turbocat.net (turbocat.net [88.99.82.50]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 93766744CF for ; Sat, 9 Mar 2019 21:40:28 +0000 (UTC) (envelope-from hps@selasky.org) Received: from hps2016.home.selasky.org (unknown [176.74.212.121]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.turbocat.net (Postfix) with ESMTPSA id 6CD1D260377; Sat, 9 Mar 2019 22:40:26 +0100 (CET) Subject: Re: USB stack getting confused To: Rozhuk Ivan , Konstantin Belousov Cc: FreeBSD Hackers , "O'Connor, Daniel" References: <3B29D870-41F9-46AF-B9F3-03106DEC417D@dons.net.au> <20190309152613.GM2492@kib.kiev.ua> <20190309162640.GN2492@kib.kiev.ua> <20190309222827.5407ddbf@rimwks> From: Hans Petter Selasky Message-ID: Date: Sat, 9 Mar 2019 22:40:02 +0100 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20190309222827.5407ddbf@rimwks> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 93766744CF X-Spamd-Bar: ------ Authentication-Results: mx1.freebsd.org; spf=pass (mx1.freebsd.org: domain of hps@selasky.org designates 88.99.82.50 as permitted sender) smtp.mailfrom=hps@selasky.org X-Spamd-Result: default: False [-6.47 / 15.00]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.000,0]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_THREE(0.00)[4]; R_SPF_ALLOW(-0.20)[+a:mail.turbocat.net]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; TAGGED_RCPT(0.00)[]; MIME_GOOD(-0.10)[text/plain]; DMARC_NA(0.00)[selasky.org]; TO_MATCH_ENVRCPT_SOME(0.00)[]; TO_DN_ALL(0.00)[]; MX_GOOD(-0.01)[cached: mail.turbocat.net]; NEURAL_HAM_SHORT(-0.88)[-0.878,0]; IP_SCORE(-3.28)[ip: (-9.49), ipnet: 88.99.0.0/16(-4.66), asn: 24940(-2.23), country: DE(-0.01)]; FREEMAIL_TO(0.00)[gmail.com]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:24940, ipnet:88.99.0.0/16, country:DE]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_TLS_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2] X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 09 Mar 2019 21:40:29 -0000 On 3/9/19 8:28 PM, Rozhuk Ivan wrote: > On Sat, 9 Mar 2019 18:26:40 +0200 > Konstantin Belousov wrote: > >> In fact I saw something similar with apcupsd and either usb/com >> adapters or native usb control card for APC UPSes. For reasons I do >> not understand, these devices are often disconnected. For older >> versions of apcupsd, it required restart for newly reattached device >> to be recreated in /dev. Sometimes it hangs whole usb stack. >> >> Newer apcupsd seems to open /dev/ugen only for the duration of the >> query, which makes the erratic behaviour is much less likely, but >> could still cause breakage when device disappear while apcupsd has it >> opened. >> > > Same problem with usb sound cards. > I try to fix it, but fail with dsp, only mixer can be fixed with small code change. > https://reviews.freebsd.org/D11140 > Hi, How will these apps detect that they need to open the new /dev/mixer node? I mean, after hang is fixed, mixer app will still try to query the old file handle forever? --HPS