ultra small alsa library

ultra small alsa library

[Marco Schuster]

hi all,

i try to run a creative extigy via the usb port on a nslu2. the nslu2 is a
arm-based (xscale) mini-server with 32mb of ram and so very resource limited
if you let services run on it.
when i now attach the extigy and play some random stuff - doesn't matter
which player - the sound is very intermittent and not recognizable. i think
this is due to massive swapping somewhere.
what are the minimum prerequisites for using s-alsa (esp. kernel!)? with
2.6.24 and debian i got segfaults.

thank you,
marco

Re: ultra small alsa library

[Robert Jarzmik]

"Marco Schuster" <marco@harddisk.is-a-geek.org> writes:

> what are the minimum prerequisites for using s-alsa (esp. kernel!)? with
> 2.6.24 and debian i got segfaults.
Hello Marco,

I'll leave others for the prerequisites.

But I can tell you I run alsa on a little smartphone with 64MBytes of memory,
with a graphical application taking 25MBytes at its start. I have no problems so
far running alsa to play songs / use my phone.

My hardware setup (mio a701 smartphone) :
 - RAM: 64 MB
 - CPU: XScale PXA272
 - Storage : SD card
 - Swap: none (poor SD card otherwise)

Sofware setup :
 - Base stolen from OPIE 4.3.1
 - custom fixes for the smartphone, nothing related to alsa

I hope that cheers you a bit about your configuration.

--
Robert

Re: ultra small alsa library

[Marco Schuster]

The problem I have is:
As soon as I try to play a mp3 via mpg123, in dmesg comes the following
error:
Division by zero in kernel.
[<c0026e2c>] (dump_stack+0x0/0x14) from [<c0026e58>] (__div0+0x18/0x20)
[<c0026e40>] (__div0+0x0/0x20) from [<c011c65c>] (Ldiv0+0x8/0x10)
[<bf0267ec>] (iso_stream_find+0x0/0x340 [ehci_hcd]) from [<bf028140>]
(ehci_urb_enqueue+0x848/0xdf4 [ehci_hcd])
[<bf0278f8>] (ehci_urb_enqueue+0x0/0xdf4 [ehci_hcd]) from [<bf005228>]
(usb_hcd_submit_urb+0x660/0x77c [usbcore])
[<bf004bc8>] (usb_hcd_submit_urb+0x0/0x77c [usbcore]) from [<bf0057fc>]
(usb_submit_urb+0x228/0x264 [usbcore])
[<bf0055d4>] (usb_submit_urb+0x0/0x264 [usbcore]) from [<bf1c2820>]
(start_urbs+0x1cc/0x308 [snd_usb_audio])
 r6:00000000 r5:c0c2dc10 r4:00000010
[<bf1c2654>] (start_urbs+0x0/0x308 [snd_usb_audio]) from [<bf1c4d78>]
(snd_usb_pcm_prepare+0xa4/0xb8 [snd_usb_audio])
 r7:00000000 r6:00000000 r5:c0c2b800 r4:c0c2dc10
[<bf1c4cd4>] (snd_usb_pcm_prepare+0x0/0xb8 [snd_usb_audio]) from
[<bf19bdc4>] (snd_pcm_do_prepare+0x1c/0x3c [snd_pcm])
 r6:00000802 r5:c13d02c0 r4:c13d02c0
[<bf19bda8>] (snd_pcm_do_prepare+0x0/0x3c [snd_pcm]) from [<bf19b96c>]
(snd_pcm_action_single+0x40/0x7c [snd_pcm])
 r4:bf1acd74
[<bf19b92c>] (snd_pcm_action_single+0x0/0x7c [snd_pcm]) from [<bf19c774>]
(snd_pcm_action_nonatomic+0x58/0x70 [snd_pcm])
 r7:00044930 r6:bf1acd74 r5:00000802 r4:c13d02c0
[<bf19c71c>] (snd_pcm_action_nonatomic+0x0/0x70 [snd_pcm]) from [<bf19eba8>]
(snd_pcm_common_ioctl1+0x664/0xf7c [snd_pcm])
 r6:c13d02c0 r5:00044930 r4:00044930
[<bf19e544>] (snd_pcm_common_ioctl1+0x0/0xf7c [snd_pcm]) from [<bf19fe18>]
(snd_pcm_playback_ioctl1+0x48c/0x4b0 [snd_pcm])
[<bf19f98c>] (snd_pcm_playback_ioctl1+0x0/0x4b0 [snd_pcm]) from [<bf19ff20>]
(snd_pcm_playback_ioctl+0x34/0x40 [snd_pcm])
[<bf19feec>] (snd_pcm_playback_ioctl+0x0/0x40 [snd_pcm]) from [<c0097e70>]
(do_ioctl+0x34/0x78)
[<c0097e3c>] (do_ioctl+0x0/0x78) from [<c0098114>] (vfs_ioctl+0x260/0x290)
 r5:00044930 r4:c0fbcbc0
[<c0097eb4>] (vfs_ioctl+0x0/0x290) from [<c009819c>] (sys_ioctl+0x58/0x78)
 r7:00004140 r6:c0fbcbc0 r5:00044930 r4:00000000
[<c0098144>] (sys_ioctl+0x0/0x78) from [<c0022de0>]
(ret_fast_syscall+0x0/0x2c)
 r8:c0022f84 r7:00000036 r6:beebb3a0 r5:beebb708 r4:00043598


Can anyone point me what goes wrong here?
Kernel is debian  2.6.24-1-ixp4xx (armv5tel).

Thanks,
Marco

Re: ultra small alsa library

[Takashi Iwai]

At Sat, 2 Aug 2008 22:34:22 +0200,
Marco Schuster wrote:
> 
> The problem I have is:
> As soon as I try to play a mp3 via mpg123, in dmesg comes the following
> error:
> Division by zero in kernel.
> [<c0026e2c>] (dump_stack+0x0/0x14) from [<c0026e58>] (__div0+0x18/0x20)
> [<c0026e40>] (__div0+0x0/0x20) from [<c011c65c>] (Ldiv0+0x8/0x10)
> [<bf0267ec>] (iso_stream_find+0x0/0x340 [ehci_hcd]) from [<bf028140>]
> (ehci_urb_enqueue+0x848/0xdf4 [ehci_hcd])
> [<bf0278f8>] (ehci_urb_enqueue+0x0/0xdf4 [ehci_hcd]) from [<bf005228>]
> (usb_hcd_submit_urb+0x660/0x77c [usbcore])
> [<bf004bc8>] (usb_hcd_submit_urb+0x0/0x77c [usbcore]) from [<bf0057fc>]
> (usb_submit_urb+0x228/0x264 [usbcore])
> [<bf0055d4>] (usb_submit_urb+0x0/0x264 [usbcore]) from [<bf1c2820>]
> (start_urbs+0x1cc/0x308 [snd_usb_audio])
>  r6:00000000 r5:c0c2dc10 r4:00000010
> [<bf1c2654>] (start_urbs+0x0/0x308 [snd_usb_audio]) from [<bf1c4d78>]
> (snd_usb_pcm_prepare+0xa4/0xb8 [snd_usb_audio])
>  r7:00000000 r6:00000000 r5:c0c2b800 r4:c0c2dc10
> [<bf1c4cd4>] (snd_usb_pcm_prepare+0x0/0xb8 [snd_usb_audio]) from
> [<bf19bdc4>] (snd_pcm_do_prepare+0x1c/0x3c [snd_pcm])
>  r6:00000802 r5:c13d02c0 r4:c13d02c0
> [<bf19bda8>] (snd_pcm_do_prepare+0x0/0x3c [snd_pcm]) from [<bf19b96c>]
> (snd_pcm_action_single+0x40/0x7c [snd_pcm])
>  r4:bf1acd74
> [<bf19b92c>] (snd_pcm_action_single+0x0/0x7c [snd_pcm]) from [<bf19c774>]
> (snd_pcm_action_nonatomic+0x58/0x70 [snd_pcm])
>  r7:00044930 r6:bf1acd74 r5:00000802 r4:c13d02c0
> [<bf19c71c>] (snd_pcm_action_nonatomic+0x0/0x70 [snd_pcm]) from [<bf19eba8>]
> (snd_pcm_common_ioctl1+0x664/0xf7c [snd_pcm])
>  r6:c13d02c0 r5:00044930 r4:00044930
> [<bf19e544>] (snd_pcm_common_ioctl1+0x0/0xf7c [snd_pcm]) from [<bf19fe18>]
> (snd_pcm_playback_ioctl1+0x48c/0x4b0 [snd_pcm])
> [<bf19f98c>] (snd_pcm_playback_ioctl1+0x0/0x4b0 [snd_pcm]) from [<bf19ff20>]
> (snd_pcm_playback_ioctl+0x34/0x40 [snd_pcm])
> [<bf19feec>] (snd_pcm_playback_ioctl+0x0/0x40 [snd_pcm]) from [<c0097e70>]
> (do_ioctl+0x34/0x78)
> [<c0097e3c>] (do_ioctl+0x0/0x78) from [<c0098114>] (vfs_ioctl+0x260/0x290)
>  r5:00044930 r4:c0fbcbc0
> [<c0097eb4>] (vfs_ioctl+0x0/0x290) from [<c009819c>] (sys_ioctl+0x58/0x78)
>  r7:00004140 r6:c0fbcbc0 r5:00044930 r4:00000000
> [<c0098144>] (sys_ioctl+0x0/0x78) from [<c0022de0>]
> (ret_fast_syscall+0x0/0x2c)
>  r8:c0022f84 r7:00000036 r6:beebb3a0 r5:beebb708 r4:00043598
> 
> 
> Can anyone point me what goes wrong here?
> Kernel is debian  2.6.24-1-ixp4xx (armv5tel).

According to the stack trace, this looks like a bug in ehci driver.
Better to ask on linux-usb ML.


Takashi