Re: em28xx issues

[Andy Walls <awalls@xxxxxxxxx>]

On Mon, 2009-01-05 at 17:33 -0700, Paul Thomas wrote:
> On Sat, Jan 3, 2009 at 10:22 AM, Paul Thomas <pthomas8589@xxxxxxxxx> wrote:
> > On Fri, Jan 2, 2009 at 9:50 AM, Paul Thomas <pthomas8589@xxxxxxxxx> wrote:
> >> On Wed, Dec 31, 2008 at 3:52 PM, Devin Heitmueller
> >> <devin.heitmueller@xxxxxxxxx> wrote:
> >>> On Wed, Dec 31, 2008 at 5:44 PM, Paul Thomas <pthomas8589@xxxxxxxxx> wrote:
> >>>> How was it working with Skype? Can we hard code the settings for testing?
> >>>>
> >>>> thanks,
> >>>> Paul
> >>>
> >>> Well, regardless of the device profile issue, it's not clear why it is
> >>> segfaulting.  In theory, it should work but you should only get a
> >>> single input available instead of being able to pick between composite
> >>> and s-video.
> >>>
> >>> I think with this device you should be able to set a modprobe option
> >>> for "debug=1" which might provide a bit more insight.
> >>>
> >>> Try this.  Unplug the device, run "make unload", and then "modprobe
> >>> em28xx".  Then plug the device in.  You should start seeing more info
> >>> in the dmesg output.  Then start the app that segfaults and report the
> >>> dmesg contents.
> >>>
> >>> Devin
> >>>
> >>> --
> >>> Devin J. Heitmueller
> >>> http://www.devinheitmueller.com
> >>> AIM: devinheitmueller
> >>>
> >>
> >> Thanks CityK. I was able to enable core_debug=1. Here is what I have
> >> in dmesg after I camstream seg faults:
> >>
> >> Em28xx: Initialized (Em28xx Audio Extension) extension
> >> em28xx #0 em28xx_capture_area_set :em28xx Area Set: (180,72)
> >> em28xx #0 em28xx_uninit_isoc :em28xx: called em28xx_uninit_isoc
> >> em28xx #0 em28xx_uninit_isoc :em28xx: called em28xx_uninit_isoc
> >> em28xx #0 em28xx_set_alternate :minimum isoc packet size: 2888 (alt=6)
> >> em28xx #0 em28xx_set_alternate :setting alternate 6 with wMaxPacketSize=2892
> >> em28xx #0 em28xx_accumulator_set :em28xx Scale: (1,1)-(179,71)
> >> em28xx #0 em28xx_capture_area_set :em28xx Area Set: (180,72)
> >> em28xx #0 em28xx_uninit_isoc :em28xx: called em28xx_uninit_isoc
> >> em28xx #0 em28xx_set_alternate :minimum isoc packet size: 2888 (alt=6)
> >> em28xx #0 em28xx_set_alternate :setting alternate 6 with wMaxPacketSize=2892
> >> em28xx #0 em28xx_accumulator_set :em28xx Scale: (1,1)-(179,71)
> >> em28xx #0 em28xx_capture_area_set :em28xx Area Set: (180,72)
> >> em28xx #0 em28xx_init_isoc :em28xx: called em28xx_prepare_isoc
> >> em28xx #0 em28xx_uninit_isoc :em28xx: called em28xx_uninit_isoc
> >> camstream[18436]: segfault at 0 ip 000000000043ea76 sp
> >> 00007fff1ca5d7a8 error 6 in camstream[400000+5a000]
> >> em28xx #0 em28xx_uninit_isoc :em28xx: called em28xx_uninit_isoc
> >> em28xx #0 em28xx_irq_callback :urb resubmit failed (error=-1)
> >> em28xx #0 em28xx_irq_callback :urb resubmit failed (error=-1)
> >> em28xx #0 em28xx_irq_callback :urb resubmit failed (error=-1)
> >> em28xx #0 em28xx_irq_callback :urb resubmit failed (error=-1)
> >> em28xx #0 em28xx_irq_callback :urb resubmit failed (error=-1)
> >>
> >> thanks,
> >> Paul
> >>
> >
> > Here is an update on the programs working with em28xx
> >
> > Working programs
> > Skype
> > UCview
> >
> > Here is the status of the other cam programs that aren't working yet:
> > camstream                 -> seg fault
> > gstreamer-properties  -> seg fault
> > cheese                      -> uses test input
> > fswebcam                  -> black screen with green stripe
> >
> > I hope this helps
> >
> > thanks,
> > Paul
> >
> 
> OK, I was able to make some more progress. I can use fswebcam on my
> x86_64 box if I comment out the input selection section. Now I'm
> trying to get fswebcam to work on my embedded arm board
> (http://opencircuits.com/Linuxstamp), but when I run it I get a kernel
> oops. I've included the oops below. I'm now using this
> (git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6.git)
> git tree.
> 
> Any ideas?
> 
> thanks,
> Paul






> linuxstamp:/home/user/fswebcam-20070108# ./fswebcam -v test.jpeg
> --- Opening /dev/video0...
> Trying source module v4l2...
> /dev/video0 opened.
> src_v4l2_get_capability,81: /dev/video0 information:
> src_v4l2_get_capability,82: cap.driver: "em28xx"
> src_v4l2_get_capability,83: cap.card: "PointNix Intra-Oral Camera"
> src_v4l2_get_capability,84: cap.bus_info: "1-1.7"
> src_v4l2_get_capability,85: cap.capabilities=0x05020041
> src_v4l2_get_capability,86: - VIDEO_CAPTURE
> src_v4l2_get_capability,93: - AUDIO
> src_v4l2_get_capability,95: - READWRITE
> src_v4l2_get_capability,97: - STREAMING
> src_v4l2_set_pix_format,530: Device offers the following V4L2 pixel formats:
> src_v4l2_set_pix_format,542: 0: YUYV (16bpp YUY2, 4:2:2, packed)
> Using palette YUYV
> src_v4l2_set_mmap,648: mmap information:
> src_v4l2_set_mmap,649: frames=4
> src_v4l2_set_mmap,694: 0 length=221184
> src_v4l2_set_mmap,694: 1 length=221184
> src_v4l2_set_mmap,694: 2 length=221184
> src_v4l2_set_mmap,694: 3 length=221184
> kernel BUG at arch/arm/mm/dma-mapping.c:495!
> Unable to handle kernel NULL pointer dereference at virtual address 00000000
> pgd = c13c4000
> [00000000] *pgd=21311031, *pte=00000000, *ppte=00000000
> Internal error: Oops: 817 [#1] PREEMPT
> Modules linked in: saa7115 v4l2_common em28xx videodev v4l1_compat
> videobuf_vmalloc videobuf_core ir_common tveeprom
> CPU: 0    Not tainted  (2.6.28-15476-g7d3b56b #2)
> PC is at __bug+0x20/0x2c
> LR is at vprintk+0x2f0/0x34c
> pc : [<c00265c0>]    lr : [<c003b078>]    psr: 60000013
> sp : c1ff1ba4  ip : c03944fc  fp : c1ff1bb0
> r10: 00000028  r9 : c1d78628  r8 : c1d1f000
> r7 : 00000020  r6 : 00000000  r5 : c1d49800  r4 : ffc09000
> r3 : 00000000  r2 : c1ff0000  r1 : 00000002  r0 : 00000030
> Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
> Control: c000717f  Table: 213c4000  DAC: 00000015
> Process fswebcam (pid: 2383, stack limit = 0xc1ff0260)
> Stack: (0xc1ff1ba4 to 0xc1ff2000)
> 1ba0:          c1ff1bc0 c1ff1bb4 c0027504 c00265b0 c1ff1c84 c1ff1bc4
> c01e2a40
> 1bc0: c0027470 c1ff1bf4 c1ff1bd4 c0053810 c003360c 00000000 c037001c
> c1c713c0
> 1be0: 00000017 c1ff0000 c1ff1c08 c1ff1c08 c1ff1bfc c02bd9b4 c0033704
> c1ff1c34
> 1c00: c1ff1c0c c02bb9a8 c003360c ffffdd0e c1ff0000 00000002 c1ff1c38
> c0376d64
> 1c20: ffffdd0e c1ff0000 c1ff1c70 c1ff1c38 c02bc0b4 c0043c5c 00000000
> 00200200
> 1c40: ffffdd0e c00443ec c1c713c0 c0398b80 00000001 00000001 c1d78000
> 00000001
> 1c60: c1dd9400 00000020 00000000 00008200 c1d78628 00000028 c1ff1cac
> c1ff1c88
> 1c80: c01e4380 c01e2904 c1ff1c94 bf036528 c004464c c1dbd3c0 c1e31400
> c1d78000
> 1ca0: c1ff1cd8 c1ff1cb0 bf036ed0 c01e40ec c1d78000 c1d7cbe0 00000000
> c1d379cc
> 1cc0: bf0150a0 bf038098 c1ff1e2c c1ff1cfc c1ff1cdc bf031904 bf036c68
> bf031000
> 1ce0: ffffffea c1d7cbe0 c1d379cc c1ff1e2c c1ff1d20 c1ff1d00 bf011ff8
> bf031850
> 1d00: c1d379c0 c1ff1e2c c044560f c044560f 00000000 c1ff1d38 c1ff1d24
> bf032b98
> 1d20: bf011d44 bf032b68 000223d0 c1ff1e18 c1ff1d3c bf0244c0 bf032b78 00000001
> 1d40: 00000000 60000013 c0398a4c c03989e0 60000013 c1d49000 00000000 c1d490d8
> 1d60: 00000001 00000001 00000000 c1d379c0 c1e0be00 c044560f c1e50ce0 c1ff1d88
> 1d80: c003624c c003360c 00000000 c1d49000 00000000 c0398a70 00000001 00000009
> 1da0: c1ff1dc4 c1ff1db0 c0191088 c0036204 c1ff0000 00000000 c1ff1dd4 c1ff1dc8
> 1dc0: c01a7720 c019103c c1ff1df0 c1ff1df0 c1ff1ddc c003f048 c003360c c1ff0000
> 1de0: 00000102 c1ff1e20 c1ff1df4 c003f150 00000000 000223d0 fffffff2 00000000
> 1e00: 00000000 c044560f 00000000 c1ff1ed4 c1ff1e1c bf026b68 bf023128 00000003
> 1e20: 00000000 c1ff1e2c c1e50ce0 00000000 00000001 00000000 00000000 00000000
> 1e40: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000001
> 1e60: 00000000 00000000 00000000 00000000 c1ff1e7c c01a76b4 c01aac20 c1ff1ea0
> 1e80: c1ff1e8c c01a76f0 c003360c c1ff1eb0 c1ff1e9c c004f4ac c003360c 00000004
> 1ea0: c1d49000 c1ff1f10 c0385478 c044560f 000223d0 c1e50ce0 c044560f c0022fe4
> 1ec0: c1ff0000 00018d94 c1ff1ef0 c1ff1ed8 bf0222e4 bf0269c4 c1e50ce0 ffffffe7
> 1ee0: 000223d0 c1ff1f10 c1ff1ef4 c00993dc bf0222ac c1e50ce0 c1f235a0 00000003
> 1f00: 000223d0 c1ff1f84 c1ff1f14 c0099d18 c009936c 00000000 c1ff1f34 c1ff1f28
> 1f20: c01a7720 c019103c c1ff1f50 c1ff1f50 c1ff1f3c c003f048 c003360c c1ff0000
> 1f40: 00000102 c1ff1f80 c1ff1f54 c003f150 c003efc4 00000000 00000001 c1e50ce0
> 1f60: fffffff7 c044560f 00000036 c0022fe4 c1ff0000 00018d94 c1ff1fa4 c1ff1f88
> 1f80: c0099d80 c0099858 00000000 00000000 00000004 00022280 00000000 c1ff1fa8
> 1fa0: c0022e40 c0099d50 00000000 00000004 00000003 c044560f 000223d0 00022414
> 1fc0: 00000000 00000004 00022280 000223d0 00000001 0000000c 00018d94 000220a0
> 1fe0: 00021540 be81e728 00013e68 40129424 80000010 00000003 00000000 00000000
> Backtrace:
> [<c00265a0>] (__bug+0x0/0x2c) from [<c0027504>] (dma_cache_maint+0xa4/0xb8)
> [<c0027460>] (dma_cache_maint+0x0/0xb8) from [<c01e2a40>]
> (usb_hcd_submit_urb+0x14c/0x890)
> [<c01e28f4>] (usb_hcd_submit_urb+0x0/0x890) from [<c01e4380>]
> (usb_submit_urb+0x2a4/0x2ac)
> [<c01e40dc>] (usb_submit_urb+0x0/0x2ac) from [<bf036ed0>]
> (em28xx_init_isoc+0x278/0x2c4 [em28xx])
>  r6:c1d78000 r5:c1e31400 r4:c1dbd3c0
> [<bf036c58>] (em28xx_init_isoc+0x0/0x2c4 [em28xx]) from [<bf031904>]
> (buffer_prepare+0xc4/0xf4 [em28xx])
> [<bf031840>] (buffer_prepare+0x0/0xf4 [em28xx]) from [<bf011ff8>]
> (videobuf_qbuf+0x2c4/0x400 [videobuf_core])
>  r7:c1ff1e2c r6:c1d379cc r5:c1d7cbe0 r4:ffffffea
> [<bf011d34>] (videobuf_qbuf+0x0/0x400 [videobuf_core]) from
> [<bf032b98>] (vidioc_qbuf+0x30/0x3c [em28xx])
>  r8:00000000 r7:c044560f r6:c044560f r5:c1ff1e2c r4:c1d379c0
> [<bf032b68>] (vidioc_qbuf+0x0/0x3c [em28xx]) from [<bf0244c0>]
> (__video_do_ioctl+0x13a8/0x389c [videodev])
>  r5:000223d0 r4:bf032b68
> [<bf023118>] (__video_do_ioctl+0x0/0x389c [videodev]) from
> [<bf026b68>] (video_ioctl2+0x1b4/0x2a4 [videodev])
> [<bf0269b4>] (video_ioctl2+0x0/0x2a4 [videodev]) from [<bf0222e4>]
> (v4l2_ioctl+0x48/0x54 [videodev])
> [<bf02229c>] (v4l2_ioctl+0x0/0x54 [videodev]) from [<c00993dc>]
> (vfs_ioctl+0x80/0x94)
>  r6:000223d0 r5:ffffffe7 r4:c1e50ce0
> [<c009935c>] (vfs_ioctl+0x0/0x94) from [<c0099d18>] (do_vfs_ioctl+0x4d0/0x4f8)
>  r7:000223d0 r6:00000003 r5:c1f235a0 r4:c1e50ce0
> [<c0099848>] (do_vfs_ioctl+0x0/0x4f8) from [<c0099d80>] (sys_ioctl+0x40/0x5c)
> [<c0099d40>] (sys_ioctl+0x0/0x5c) from [<c0022e40>] (ret_fast_syscall+0x0/0x2c)
>  r6:00022280 r5:00000004 r4:00000000
> Code: e1a01000 e59f000c eb0052c5 e3a03000 (e5833000)
> ---[ end trace 68fb0b4324720f98 ]---


Well, I don't have kernel 2.6.28 code lying around, but it looks like a
BUG() that was being emitted Oops'ed instead of completing.

The ARMv5te disassmbly of the code bytes show this:

   0:   e1a01000        mov     r1, r0
   4:   e59f000c        ldr     r0, [pc, #12]   ; 0x18
   8:   eb0052c5        bl      0x14b24
   c:   e3a03000        mov     r3, #0  ; 0x0
  10:   e5833000        str     r3, [r3]       <=== Ooops here

r3 is 0/NULL in the Oops dump, but that just means there was a problem
with the BUG() call (I think).  That doesn't help much.

Without the 2.6.28 ARM kernel source at hand, I can't say much more
aside from the em82xx_init_isoc() is the first v4l-dvb driver function
encountered going through the backtrace and that it looks like the chain
of events was spurred by the memory mapping activity:

> ...
>src_v4l2_set_mmap,694: 3 length=221184


Regards,
Andy



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