On Oct 2, 2009, at 4:20 PM, hermann pitton wrote:
Am Freitag, den 02.10.2009, 13:47 +0200 schrieb Jean Delvare:
...
While investigating another issue, I have noticed the following
message
in the kernel logs of a saa7134 user:
i2c-adapter i2c-0: Invalid 7-bit address 0x7a
The address in question is attempted by an IR device probe, and is
only
probed on SAA7134 adapters. The problem with this address is that
it is
reserved by the I2C specification for 10-bit addressing, and is thus
not a valid 7-bit address. Before the conversion of ir-kbd-i2c to the
new-style i2c device driver binding model, device probing was done by
ir-kbd-i2c itself so no check was done by i2c-core for address
validity. But since kernel 2.6.31, probing at address 0x7a will be
denied by i2c-core.
So, SAA7134 adapters with an IR device at 0x7a are currently broken.
Do we know how many devices use this address for IR and which they
are? Tracking the changes in the source code, this address was added
in kernel 2.6.8 by Gerd Knorr:
http://git.kernel.org/?p=linux/kernel/git/tglx/history.git;a=commitdiff;h=581f0d1a0ded3e3d4408e5bb7f81b9ee221f6b7a
So this would be used by the "Upmost Purple TV" adapter. Question is,
are there other?
Yes, currently 0x7a is only used by the Upmost Purple TV (Yuan
Tun800).
Here are some more details.
http://archives.devshed.com/forums/linux-97/troubles-with-yuan-tun900-board-detected-as-upmost-purple-tv-1283673.html
Support for the card and the i2c remote was added by Wang-Chan Chen.
For testers it is useful to know that the card is still not fully
supported.
It has a NEC D64083GF video enhancer converting TV baseband video from
tuner to S-Video and shares the vmux = 7 with the S-Video input.
By default it comes up in external S-Video input mode.
There is a Pericom videomux on it and we don't know how to switch it.
Chen used to boot at first windows, switched there to tuner input and
rebooted to GNU/Linux ...
Some web research has pointed me to the Yuan TUN-900:
http://www.linuxtv.org/pipermail/linux-dvb/2008-January/023405.html
but it isn't clear to me whether the device at 0x7a on this adapter
is
the same as the one on the Purple TV. And saa7134-cards says of the
TUN-900: "Remote control not yet implemented" so maybe we can just
ignore it for now.
Yes, that card has a device at 0xf4/0x7a too.
I asked to test the remote with the Upmost Purple TV entry, but never
got a reply. As we know these days, radio amux is wrong too on Yuan
TUN900 card=66.
Last contact to Chen was four years back, but he confirmed that both
cards have the same PCI subsystem. Some bytes in the eeprom, meaning
unknown, are different, though.
If we have to, I could make i2c-core more permissive, but I am rather
reluctant to letting invalid addressed being probed, because you
never
know how complying chips on the I2C bus will react. I am OK
supporting
invalid addresses if they really exist out there, but the impact
should
be limited to the hardware in question.
If we only have to care about the Upmost Purple TV, then the
following
patch should solve the problem:
For what is known so far.
Acked-by: hermann pitton <hermann-pitton@xxxxxxxx>
Seems like a sane thing to do to me too, and I've not seen nor heard
of any other devices that use 0x7a. (Hell, I wasn't even aware of
these ones 'til now).
Acked-by: Jarod Wilson <jarod@xxxxxxxxxx>
--
Jarod Wilson
jarod@xxxxxxxxxxxx
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