Wow, thanks!
On 03/04/2011 11:37 PM, Andrew de Quincey wrote:
Hi, this has been annoying me for some time, so this evening I fixed
it. If you use one of the above dual tuner devices (e.g. KWorld 399U),
you get random tuning failures and i2c errors reported in dmesg such
as:
[...]
Adding a "bus lock" to af9015_i2c_xfer() will not work as demod/tuner
accesses will take multiple i2c transactions.
Therefore, the following patch overrides the dvb_frontend_ops
functions to add a per-device lock around them: only one frontend can
now use the i2c bus at a time. Testing with the scripts above shows
this has eliminated the errors.
This have annoyed me too, but since it does not broken functionality
much I haven't put much effort for fixing it. I like that fix since it
is in AF9015 driver where it logically belongs to. But it looks still
rather complex. I see you have also considered "bus lock" to
af9015_i2c_xfer() which could be much smaller in code size (that's I
have tried to implement long time back).
I would like to ask if it possible to check I2C gate open / close inside
af9015_i2c_xfer() and lock according that? Something like:
typical command sequence:
>> FE0 open gate
>> FE0 write reg
>> FE0 close gate
>> FE1 open gate
>> FE1 read reg
>> FE1 close gate
if (locked == YES)
if (locked_by != caller FE)
return error locked by other FE
else (locked_by == caller FE)
allow reg access
if (gate close req)
locked = NO
locked_by = NONE
else (locked == NO)
locked = YES
locked_by = caller FE
allow reg access
Do you see it possible?
thanks
Antti
--
http://palosaari.fi/
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