Shrijeet Mukherjee wrote:
>>To: [EMAIL PROTECTED]
>>Subject: [V4L] system hang in bttv driver on
>>modprobe. PCI problem?
>>
>>
>>I hope someone can point me in the direction of
>>some help. The problem
>>is easy to reproduce, but I have no error
>>messages, just the system
>>locks up solid (no oops!) I have SGI KDB
>>installed and functional but it
>>does not come up when the hang occurs either.
>>
>>Versions:
>> started with redhat 7.3 standard kernel
>>(2.4.18++, with bttv 0.7.xxx)
>> then tried 2.4.19 linus tree with v4l2 &
>>bttv-0.8.45... no change.
>>
>>I started editing the bttv driver. and noticed
>>that it hangs in the file
>>bttv-driver.c in the init_bt848 routine at the
>>line which does
>>"btwrite(val,BT848_E_SCLOOP);" If I comment
>>out the line, it will hang
>>on the next line, If I comment that one, it
>>will hang on the one after
>>that, etc...
>>
>>These lines to write to registers on the ATI TV
>>Wonder Card (PCI id
>>00:09.0 which has a BT878A chip on it.) It
>>seems able to do a couple of
>>writes and then hang.
>>
>>grumpy% lspci
>>00:00.0 Host bridge: VIA Technologies, Inc.
>>VT82C693A/694x [Apollo
>>PRO133x] (rev c2)
>>00:01.0 PCI bridge: VIA Technologies, Inc.
>>VT82C598/694x [Apollo
>>MVP3/Pro133x AGP]
>>00:04.0 ISA bridge: VIA Technologies, Inc.
>>VT82C596 ISA [Mobile South]
>>(rev 12)
>>00:04.1 IDE interface: VIA Technologies, Inc.
>>Bus Master IDE (rev 06)
>>00:04.2 USB Controller: VIA Technologies, Inc.
>>USB (rev 08)
>>00:04.3 Host bridge: VIA Technologies, Inc.
>>VT82C596 Power Management
>>(rev 20)
>>00:09.0 Multimedia video controller: Brooktree
>>Corporation Bt878 Video
>>Capture (rev 11)
>>00:09.1 Multimedia controller: Brooktree
>>Corporation Bt878 Audio Capture
>>(rev 11)
>>00:0b.0 Multimedia audio controller: Creative
>>Labs SB Live! EMU10k1 (rev 08)
>>00:0b.1 Input device controller: Creative Labs
>>SB Live! MIDI/Game Port
>>(rev 08)
>>00:0e.0 Ethernet controller: 3Com Corporation
>>3c905B 100BaseTX [Cyclone]
>>(rev 30)
>>01:00.0 VGA compatible controller: Matrox
>>Graphics, Inc. MGA G400 AGP
>>(rev 04)
>>grumpy%
>>
>>I would appreciate any ideas on how to proceed,
>>or pointers to people
>>who might be willing to help.
>>
>>
>>
>
>The O_SCLOOP register is just setting the video
>filter that it will use for Automatic Gain
>Control and Horizontal (line) filtering. Since
>you probably do not have video turned on yet, I
>would not suspect it yet.
>
>If you are using .8.45 the only thing that
>happens before in the init function and is
>possible suspicious is the setting of the DMA
>bits for the DMA controller.
>
>That is what I would try to comment out, or in
>the very least move it down further below to see
>if it changes things ..
>
>
I am not sure what you want me to comment out.
Is it one of these routines?
pci_set_dma_mask(dev, 0xffffffff)
request_mem_region(...)
if (!pci_dma_supported(dev,0xffffffff)) ...
??
>Also .. in the generic startup code up there, do
>you see any error messages like "Oops .. no DMA
>found .." or things like that ?
>
>
Initially there were no messages. I removed the KERN_INFO and KERN_DEBUG
parameters from printk lines, and inserted "about to" printk's to trace
where it hangs
After reading a bit about PCI quirks, I also added a test in bttv-driver.c
" if (isa_dma_bridge_buggy)
printk( "bttv: Host bridge has buggy ISA DMA\n");
" similar to the ones for the VSFX and triton tests there...
now I have (transcribed):
grumpy# modprobe bttv
<date> Linux video capture interface: v1.00
bttv: host bridge is VIA Technologies Inc. VT82C693A/694x [Apollo 133x]
bttv: host bridge is VIA Technologies Inc. VT82C596 Power Management
bttv: host bridge has buggy ISA DMA
bttv: host bridge needs VSFX enabled
PCI: Enabling device - 00:09.0 (0004->0006)
bttv0: detected: ATI TV Wonder [card=63, autodetected]
bttv0: enabling VSFX
bttv0: risc main @ 12112000
about to btwrite(val, BT848_E_SCLOOP)
---------- <HANG> ----------------------------------
notes:
/etc/modules.conf: options bttv bttv_debug=1
irq_debug=1 v4l2=2 vsfx=1
>PPS: How do you know it is an 878A ? the pci
>parameters do not actually specify it .. and I
>get the same message as you do, but assumed that
>it was the 878 not the 878A ..
>
>
>
I took the card out of the machine There are two chips on it that say:
Conexant Fusion 878A E197817-1 Taiwan,
Micronas MSP 3445G 881162JS LHX
respectively. On the other side of the card, there is a metal
box with "PHILIPS" printed on it, and I live in North America.
P.S. If someone can tell me how to get Redhat to print kernel info and debug
messages, it would be really helpful!
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