[linux-dvb] Re: Nebula installation and nxt6000 fault

[Holger Waechtler <holger@convergence.de>]

Niklas Peinecke wrote:
> Holger Waechtler wrote:
>
> > Jamie Honan wrote:
> >
> > > > #modprobe bttv card=0x68 i2c_hw=1
> > >
> > >
> > >
> > > > dmesg output ============>
> > > > bttv: driver version 0.9.12 loaded
> > > > bttv: snapshot date 2003-12-08
> > >
> > >
> > >
> > > > [<e0c8612b>] bttv_i2c_xfer+0x9b/0xc0 [bttv]
> > > > [<e0c92000>] bttvs+0x0/0x4cc0 [bttv]
> > > > [<e0c92000>] bttvs+0x0/0x4cc0 [bttv]
> > > > [<e0c92040>] bttvs+0x40/0x4cc0 [bttv]
> > > > [<e0c92004>] bttvs+0x4/0x4cc0 [bttv]
> > > > [<c02ecf29>] i2c_transfer+0x39/0x80 [kernel]
> > > > [<e0c92004>] bttvs+0x4/0x4cc0 [bttv]
> > > > [<e0ca61a4>] master_xfer+0x34/0x50 [dvb-bt8xx]
> > > > [<e0c92004>] bttvs+0x4/0x4cc0 [bttv]
> > > > [<e0dcc269>] pll_write+0x59/0xa0 [nxt6000]
> > > > [<e0dccf0b>] nxt6000_attach+0x9b/0x200 [nxt6000]
> > > > [<e0c9cc78>] try_attach_device+0x38/0x80 [dvb-core]
> > > > [<e0c9cded>] probe_device_on_all_busses+0x1d/0x30 [dvb-core]
> > > > [<e0ca42e0>] dvb_i2c_mutex+0x0/0x20 [dvb-core]
> > > > [<e0c9cfe9>] dvb_register_i2c_device_Rde0504aa+0x59/0x90 [dvb-core]
> > > > [<e0dcd978>] __ksymtab+0x0/0x20 [nxt6000]
> > > > [<e0dcd0f0>] nxt6000_init+0x20/0x50 [nxt6000]
> > > > [<e0dcce70>] nxt6000_attach+0x0/0x200 [nxt6000]
> > > > [<e0dcd070>] nxt6000_detach+0x0/0x60 [nxt6000]
> > > > [<c01f5762>] sys_init_module+0x652/0x6e0 [kernel]
> > > > [<e0dcd96c>] .kmodtab+0x0/0xc [nxt6000]
> > > > [<e0dcc060>] nxt6000_write+0x0/0xa0 [nxt6000]
> > > > [<c01e0683>] system_call+0x33/0x40 [kernel]
> > >
> > >
> > >
> > > This bug is caused by the i2c hardware write routine in
> > > the bttv driver. It can't handle writing a zero length
> > > message to an i2c address.
> >
> >
> > ough - that's an important issue; some of our frontend driver initiate 
> > their probing by a 'i2c ping' - they are looking whether a 
> > zero-length/adress-only message is properly acknowledged by the chip...
> >
> > Holger
> By "zero-length/adress-only message" do you mean a single i2c write 
> operation consisting only of an address byte with no further data bytes?
yes. This is used when the probed chip has no known id register we can 
read and when the i2c address is unique.

Holger



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