From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guido Trentalancia Subject: Re: Hercules P32 DJ: severe sound distortion during MIDI transfers Date: Fri, 22 Mar 2019 17:02:14 +0100 (CET) Message-ID: <1284835663.62489.1553270538983@pim.register.it> References: <1553114844.12865.6.camel@trentalancia.com> <1335514032.30698.1553207267014@pim.register.it> <53EC51B6-618E-47B4-95E8-B24BECEEBC98@trentalancia.com> <1553262288.26146.4.camel@trentalancia.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from webmailsmtp.register.it (webmailsmtp28.register.it [81.88.63.153]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 50C7FF8076F for ; Fri, 22 Mar 2019 17:02:19 +0100 (CET) In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: "Alsa-devel" To: Takashi Iwai Cc: alsa-devel@alsa-project.org, clemens@ladisch.de List-Id: alsa-devel@alsa-project.org But the bandwidth taken by MIDI should be very small compared to the one taken by the 48KHz audio stream, so that sounds very strange ! Obviously it's the multiplexing of audio and MIDI which fails, but I am not much into the USB drivers, either audio or core... The USB root hub should be 2.0, according to lsusb output: Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Sounds pointless to try other ports since they are all of the same kind... The important point here is that, in my opinion, a USB core driver bug seems less probable that a USB audio driver bug because the affected range is very wide (4.12 - 5.0) and at the same time the USB core driver has been tested very widely everyday by virtually all Linux users. What should I do next ? Guido > On the 22nd of March 2019 at 16.14 Takashi Iwai wrote: > > > On Fri, 22 Mar 2019 16:05:17 +0100, > Guido Trentalancia wrote: > > > > I suppose the Fedora 29 kernels are included in the range I tested as broken, > > i.e. 4.12 -- 5.0. > > > > So, there is something triggering it on my system and not the other, maybe the > > USB system as pointed out by Clemens. > > You can try different USB ports, too, e.g. if there are both USB 3.0 > and 2.0 ports. > > > I'll make some research on the two USB systems... > > > > I would also like to try USB Audio driver from kernel 3.0.1. > > > > What else do you suggest? > > If any, the problem is rather about the USB core side (likely the host > driver), not the USB audio driver. I can imagine some bandwidth > management or iosc transfer problem. > > > Takashi > > > > > Guido > > > > Il 22 marzo 2019 15:58:23 CET, Takashi Iwai ha scritto: > > > > On Fri, 22 Mar 2019 15:54:03 +0100, > > Guido Trentalancia wrote: > > > > As already explained, I have tested the following kernels: > > > > - kernel 5.0.2 -----> BROKEN > > - kernel 4.17.10 --> BROKEN > > - kernel 4.12.9 ---> BROKEN > > > > So, it's been around for very long. > > > > What do you suggest doing? > > > > But which kernel is used for another user who can use without the > > problem? I suppose they use the recent kernel with Fedora? > > > > I have found reports on the web about similar problems (with other audio > > interfaces) with kernels>3.0.0. > > > > Such a regression should have been reported earlier, otherwise it > > becomes more and > > more difficult to catch up... > > > > thanks, > > > > Takashi > > > > Regards, > > > > Guido > > > > Il 22 marzo 2019 15:47:36 CET, Takashi Iwai ha scritto: > > > > On Fri, 22 Mar 2019 14:44:48 +0100, > > Guido Trentalancia wrote: > > > > Hello Takashi. > > > > I have carried out the test that you proposed... > > > > My reply follows your quoted text. > > > > On Fri, 22/03/2019 at 11.12 +0100, Takashi Iwai wrote: > > On Fri, 22 Mar 2019 11:04:01 +0100, > > Guido Trentalancia wrote: > > > > Hello Takashi, > > > > I am using the latest version of everything, including kernel and > > > > ALSA > > userspace library / tools. > > > > The other user has exactly the same hardware and has tested same > > firmware > > (both 1.36 and latest > > 1.46), but with Fedora 29 and it is working. > > > > Perhaps Fedora 29 has a different version of the ALSA library, I > > will find > > out, try to downgrade, test again and report back. > > > > Yes, that'd be really helpful. If aligning the software doesn't fix > > the issue, it's either because of the hardware or the difference of > > usage patterns. > > > > I have tested exactly the same ALSA userspace library and plugins > > distributed by Fedora 29 and it does NOT work ! > > > > As already explained, the usage pattern is > > exactly the same between me > > and the user which is not experiencing this severe problem. > > > > Also, the hardware is the same: Hercules P32 DJ (with exactly the same > > firmware version 1.46 which is the latest). > > > > So, the conclusion is that it must be a kernel bug ! I was expecting > > this, as already pointed out in previous messages. > > > > Did you test the > > very same kernel, too? Without that confirmation, no > > one can conclude that at all... > > > > If the kernel makes difference, you can try identify which kernel > > version starts showing the problem, and at best, do git bisection. > > > > thanks, > > > > Takashi > > > > Can you please help me fix this bug since you wrote the driver and/or > > are maintaining it ? > > > > Thanks, > > > > Guido > > > > thanks, > > > > Takashi > > > > Guido > > > > Il 22 marzo 2019 10:53:11 CET, Takashi Iwai ha > > scritto: > > > > On Fri, 22 Mar 2019 > > 10:17:17 +0100, > > Guido Trentalancia wrote: > > > > It cannot be a firmware bug, as you say, because: > > > > - it does NOT happen on Windows! > > > > It doesn't mean that the device behaves correctly as > > advertised. > > > > - it does NOT even always happen on Linux: other users > > (with different kernel > > / ALSA > > library) are not experiencing the same problem; > > - it happens with several firmware versions, including the > > latest one (1.36 > > and 1.46). > > > > So it is either a bug in ALSA kernel driver, USB sound > > driver (more likely) or > > ALSA library. > > > > Now, you are in charge of the USB sound driver, can you > > please double check?? > > > > If it doesn't happen for other users with the very same device, > > you'd > > need to identify what's the difference > > between your case and > > others. > > For example, if the difference of alsa-lib matters, you can try > > > > the > > very same condition. > > > > This kind of bug can't be easily debugged without the actual > > hardware, unfortunately. > > > > Takashi > > > > Regards, > > > > Guido > > > > Il 22 marzo 2019 09:55:52 CET, Takashi Iwai > ha scritto: > > > > On Thu, 21 Mar 2019 23:27:46 +0100, > > Guido Trentalancia wrote: > > > > I wonder if this might be due to a bug in the > > "USB Audio Driver for Alsa"? > > > > https://git.kernel.org/pub/scm/linux/kernel/git/t > > orvalds/linux.git/tree/sound/usb > > > > https://git.kernel.org/pub/scm/linux/kernel/git/t > > iwai/sound.git/tree/sound/usb > > > > More likely a buggy firmware of your USB audio device > > :) > > > > From the driver implementation POV, both audio and > > MIDI devices are > > handled by individual endpoints, hence they shouldn't > > conflict. > > > > Or another possibility would be some USB > > host side > > issue like the > > bandwidth. But > > it's a MIDI stream that is very low data rate, so this > > sounds also unlikely... > > > > thanks, > > > > Takashi > > > > Guido > > > > On the 20th of March 2019 at 21.47 Guido > > Trentalancia > > > > > Hello. > > > > I am hitting a very serious bug (ALSA kernel > > driver or ALSA library) > > > > when using the Hercules P32 DJ audio > > interface. > > > > The sound is severely distorted during MIDI > > transfers. > > > > To reproduce: > > > > + start playing something in a first > > console: > > > > console1# AUDIODEV=hw:2,0 play audio.wav > > > > + the audio plays fine > > > > + now start "amidi" in a second console > > while the above track is still > > playing > > > > console2# > > amidi -p hw:2,0,0 -d > > > > + the sound is now severely distorted > > (basically noise, with some > > hard- > > to-distinguish features resembling the > > original track) until "amidi" > > is > > interrupted ! > > > > > _______________________________________________ > Alsa-devel mailing list > Alsa-devel@alsa-project.org > https://mailman.alsa-project.org/mailman/listinfo/alsa-devel