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Mon, 20 Jul 2026 06:39:17 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id kCdNH5XCXWpDegAAD6G6ig (envelope-from ); Mon, 20 Jul 2026 06:39:17 +0000 Date: Mon, 20 Jul 2026 08:39:17 +0200 Message-ID: <87tspuqi5m.wl-tiwai@suse.de> From: Takashi Iwai To: Zhang Heng Cc: Takashi Iwai , Gordon Chen , perex@perex.cz, tiwai@suse.com, kees@kernel.org, jussi@sonarnerd.net, hulianqin@vivo.com, i@rong.moe, g@b4.vu, cryolitia@uniontech.com, pav@iki.fi, linux-sound@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] usb-audio: Fix boot-time crackling for Generic USB Audio device In-Reply-To: <9fc3da84-0985-4357-93bb-ce90a86b01de@kylinos.cn> References: <20260713081048.189281-1-zhangheng@kylinos.cn> <18c1dc0246121271.5ea4dc9a201e9dce.cafe1c196d712416@GordonMsi> <87zezvx73v.wl-tiwai@suse.de> <878q77s6jp.wl-tiwai@suse.de> <9fc3da84-0985-4357-93bb-ce90a86b01de@kylinos.cn> User-Agent: Wanderlust/2.15.9 (Almost Unreal) Emacs/30.2 Mule/6.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-Spam-Flag: NO X-Rspamd-Action: no action X-Spam-Level: X-Spamd-Result: default: False [-3.51 / 50.00]; BAYES_HAM(-3.00)[100.00%]; MID_CONTAINS_FROM(1.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; R_DKIM_ALLOW(-0.20)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; RBL_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:104:10:150:64:97:from]; RCVD_TLS_ALL(0.00)[]; ARC_NA(0.00)[]; RCPT_COUNT_TWELVE(0.00)[14]; MIME_TRACE(0.00)[0:+]; FUZZY_RATELIMITED(0.00)[rspamd.com]; RCVD_VIA_SMTP_AUTH(0.00)[]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; FROM_HAS_DN(0.00)[]; FREEMAIL_CC(0.00)[suse.de,gmail.com,perex.cz,suse.com,kernel.org,sonarnerd.net,vivo.com,rong.moe,b4.vu,uniontech.com,iki.fi,vger.kernel.org]; TO_DN_SOME(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[imap1.dmz-prg2.suse.org:helo,imap1.dmz-prg2.suse.org:rdns,suse.de:mid,suse.de:dkim]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DKIM_TRACE(0.00)[suse.de:+] X-Rspamd-Server: rspamd2.dmz-prg2.suse.org X-Rspamd-Queue-Id: E58E479DE1 X-Spam-Score: -3.51 On Mon, 20 Jul 2026 04:23:25 +0200, Zhang Heng wrote: > > > > Please add some comment why the device needs this workaround. > > IIUC, the reason is different from the others in your case. > > > > Also, please verify that the problem is reproduced in the latest > > upstream kernel, and the workaround works as expected there, too. > > > > > > thanks, > > > > Takashi > > >> --- a/sound/usb/quirks.c > >> +++ b/sound/usb/quirks.c > >> @@ -1938,6 +1938,10 @@ void snd_usb_endpoint_start_quirk(struct > snd_usb_endpoint *ep) > >> ep->type == SND_USB_ENDPOINT_TYPE_SYNC) > >> ep->skip_packets = 4; > >> > >> + if (ep->chip->usb_id == USB_ID(0x1e0b, 0xd01e) && > >> + ep->type == SND_USB_ENDPOINT_TYPE_SYNC) > >> + ep->skip_packets = 4; > >> + > > Let me update the current status: that piece of code can be > omitted. I have applied your test patch, but there is no > change. It might be that your patch has no effect on this > device. I tested with version v7.2-rc1. To be honest, > without any modification, the problem becomes a reproducible > stutter plus crackling noise. After applying my fix, it > becomes a probabilistic stutter (still with a relatively > high probability of recurrence), but when there is no > stutter, there is also no crackling noise. So I am sure > that this patch is at least useful, but it does not > perfectly solve the problem. I am still trying to resolve > the stutter issue, and I wonder if it is due to resource > contention during boot? This problem only occurs at boot > time; after entering the system, it disappears. OK, if the workaround is no solid solution, it's not worth to take. Have you tried lowlatency=0 option? If it's an implicit fb and about the playback, it might stabilize. thanks, Takashi