On Thu, 25 May 2017 18:51:10 +0200, Cheng Sun wrote: > > On 25 May 2017 at 17:31, Takashi Iwai <tiwai@xxxxxxx> wrote: > > On Thu, 25 May 2017 17:43:44 +0200, > > Cheng Sun wrote: > >> > >> On 25 May 2017 14:49, "Takashi Iwai" <tiwai@xxxxxxx> wrote: > >> > > >> > On Wed, 24 May 2017 21:13:46 +0200, > >> > Cheng Sun wrote: > >> > > > >> > > Hi all, > >> > > > >> > > The following commit (released in v1.1.4) introduced an issue where a > >> > > client compiled against a 32-bit (x86) compile of alsa-lib cannot use > >> > > the same dmix as a client compiled against a 64-bit alsa-lib. > >> > > > >> > > 1a9bd0f0448106b917ae7f7bedccfcbf6ce84802 > >> > > > >> > > The error message is: > >> > > > >> > > ALSA lib pcm_dmix.c:1077:(snd_pcm_dmix_open) unable to create IPC > >> > > shm instance > >> > > > >> > > The following forum post (not mine) describes the symptoms of the > >> > > issue in more detail (although the git commit the poster specified is > >> > > not correct): > >> > > > >> > > > >> https://forums.gentoo.org/viewtopic-p-8072290.html?sid=c2fbca45102933ddf9ca7cf8b6713e56 > >> > > >> > There is a known problem when you mix up two alsa-lib versions because > >> > of the changes in dmix shmem struct. The solution should upgrade all > >> > users. > >> > >> (Apologies for duplicate email --accidentally sent the first reply to the > >> wrong address.) > >> > >> Arch Linux has upgraded both its 32 and 64 bit packages to v1.1.4, and I'm > >> still experiencing this problem. > >> > >> While bisecting the bug I linked against two compiles of the same alsa-lib > >> versions each time. > >> > >> Let me know if I can provide any other information. > > > > OK, at first to see whether it's the issue of the struct size > > mismatch, check the following patch. If it is, you'll see the error > > message. To be sure, check both cases: 64bit -> 32bit, and 32bit -> > > 64bit. > > The behaviour is different for the two cases. > > 1) If 64bit client is started first, then the 32bit client prints the following: > > magic mismatch: shmptr=a15ad4f0, expected=a15ad4ec > ALSA lib pcm_dmix.c:1077:(snd_pcm_dmix_open) unable to create IPC shm instance > > 2) If 32bit client is started first, then the 64bit client only prints: > > ALSA lib pcm_dmix.c:1077:(snd_pcm_dmix_open) unable to create IPC shm instance > > I've added some further print statements and it turns out that this is > because the "return err;" on line 115 is triggered. Hm, so at least the struct size difference is a problem. Doese the patch below change the behavior? Takashi --- diff --git a/src/pcm/pcm_direct.h b/src/pcm/pcm_direct.h --- a/src/pcm/pcm_direct.h +++ b/src/pcm/pcm_direct.h @@ -66,7 +66,6 @@ typedef struct { char socket_name[256]; /* name of communication socket */ snd_pcm_type_t type; /* PCM type (currently only hw) */ int use_server; - unsigned int recoveries; /* no of executed recoveries on slave*/ struct { unsigned int format; snd_interval_t rate; @@ -113,6 +112,7 @@ typedef struct { unsigned long long chn_mask; } dshare; } u; + unsigned int recoveries; /* no of executed recoveries on slave*/ } snd_pcm_direct_share_t; typedef struct snd_pcm_direct snd_pcm_direct_t; _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
