[mythtv-users] Re: mythtv 0.14, bttv 0.9.12/13 + Kernel 2.6.3-4 - low brightness red screen on channel change

Bruce Markey bjm at lvcm.com
Sat Mar 27 13:38:24 EST 2004

scunacc wrote:
> Dear Bruce et al.,
>>There is also now a release of bttv-0.9.13 which has code to
>>restore the state which was not in 0.9.12.
> I had already downloaded and built 0.9.13 (look at the logs I sent with
> the original message), and that alone didn't solve the problem.

Well, the excerpt of code that I included clearly is the fix
for this issue and the fix that Gerd described. I'd never seen
this problem ever before 0.9.12, saw it dozens of times with
0.9.12 in a brief period of about a week then went back to 0.9.11.
I actually did see this problem a couple times with 2.4.24 and
0.9.11 but it was very rare.

The problem is that the correct values don't get restored when
the driver needs to reset. This can happen after starting, a change
or if there is an error during normal operation such as a timeout
or an overflow. With 0.9.12 the colors would be distorted on about
1 out of 10 or 20 channel changes. 

With 0.9.13:
Mar 26 21:59:20 moktoo kernel: bttv: driver version 0.9.13 loaded

I can change channels hundreds of times on never see distorted
colors. Further, it doesn't screw up if there is an error during

Mar 26 22:03:04 moktoo kernel: bttv0: timeout: drop=14 irq=14029/14029, risc=01a
c007c, bits: HSYNC OFLOW FDSR
Mar 26 22:03:04 moktoo kernel: bttv0: reset, reinitialize
Mar 26 22:03:04 moktoo kernel: bttv0: PLL can sleep, using XTAL (28636363).

The "reset, reinitialize" is the key.

So, I posted to let everyone else know that this is fixed in 13. 

> I'll also take a look at the code fragment you sent to see if it matches
> the one in the 13 version I downloaded 2 days ago. If it does, then I'm
> not as hopeful of a solution as yet, since I may have already tried that
> code then...

The problem may be that you say you "downloaded and built 0.9.13"
but that doesn't necessarily mean that the new version of the
module was used. The current modules for v4l2-common, btcx-risc
and bttv need to be unloaded with rmmod. "make install" from the
driver tarball puts the new modules in "v4l2/" rather than
"kernel/drivers/media/video/" so there will be two version of
these modules. I move the old ones out of the way so there will
only be one bttv.o under /lib/modules/<version>/ , Next, you need
to do a "depmod -a" to update the module info then load the new
modules. After that, "grep bttv /var/log/syslog" to see that it
loaded properly. You should see "bttv: driver version 0.9.13 loaded"
in your messages. If you truly are running 13 you should never see
this color distortion problem.

--  bjm

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