Re: KWorld ATSC 115 all static

[Mauro Carvalho Chehab <mchehab@infradead.org>]

On Tue, 03 Feb 2009 01:03:58 -0500
CityK <cityk@rogers.com> wrote:

> David Engel wrote:
> > As far as I can tell, this thread petered out without a resolution.  
> > CityK later posted on avsforum, however, that analog on his card was
> > after more changes by Hans.  I'm confused.  Is analog on the KWorld
> > 115 supposed to be working again or not?  I saw that some changes by
> > Hans made it into the main Hg repository, but as of yesterday, analog
> > still didn't work for me.
> >   
> 
> Nope, this thread is still alive and well -- I posted to it last Thurs
> (?), and Mauro replied, but I haven't had time to follow up with this
> since then. Anyway, here's a synopsis of the situation:
> 
> - Hans had a first go at the saa7134 (and related modules) in this work
> was in his v4l-dvb-saa7134 test repo .... these initial changes,
> unfortunately, were NOT sufficient on their own to get analog TV
> working. These changes did, however, get pulled into the mainline of v4l-dvb
> 
> - Hans' second attempt at this is found in his v4l-dvb-kworld test repo
> ... testing this code revealed that analog tv did indeed work again with
> tvtime ... I also noted that there seems to be a bit of redundancy now
> in terms of the tuner being initialized twice
> 
> - Mauro created a patch intended to be applied against mainline ... I
> tested and analog tv did NOT work
> 
> - On Sunday Jan 25th I sent a lengthy message to the list, outlining
> some debug results etc. and also informing Mauro that his patch did NOT
> work ... I know that, at the very least, Trent and Hermann received that
> message, because they quoted from it in further discussion about the i2c
> gate (the inherent underlying problem at the heart of the issue).
> 
> - A few days later, scanning through the #irc logs, I caught a
> discussion, regarding Mauro's patch getting pulled into mainline, and
> the discussion seemed to indicate that there was some confusion as to
> what I had said worked and what doesn't. This surprised me for I had
> been pretty explicit in my Jan 25th mail list message. The other
> alternative was perhaps they simply had missed that message...so, in
> order to clear the situation up, I went to the mailing list archive to
> find a link for my message...only to discover it was NEVER
> achieved/recorded....grrrrr. So I'm at a complete loss as to who
> actually saw the Jan 25th message and who didn't.
> 
> - Further, somewhat concurrently, I discovered that (with Hans' kworld
> test repo) analog TV was ONLY working with tvtime ... xawtv/motv and
> kdetv were borked (I don't use Myth, so I have no idea what its status
> would be ... though, I'd suspect that it works like tvtime). I quickly
> traced this problem to be related to dga and Xv. A very similar
> situation with these apps existed several years ago when the proprietary
> X drivers from nvidia and ati removed dga functionality from their
> respective drivers (for some background read:
> http://www.nvnews.net/vbulletin/showthread.php?t=68232, and also the
> relevant portion of the FAQ from the nvidia readme:
> ftp://download.nvidia.com/XFree86/Linux-x86_64/180.27/README/chapter-07.html),
> however, the basic nv driver would still function. Nvidia would later
> provide a workaround to this issue in their driver.
> So, in this modern day occurrence of this similar error/bug, the obvious
> first test is to eliminate the proprietary driver from the equation.
> However, the test result with the nv driver was the same -- borked
> motv/xawtv and kdetv. I reported this, saying that I suspected that a
> something may have been introduced somewhere resulting in this issue
> with these apps resurfacing. This is why I asked that Hans' kworld repo
> NOT be pulled into mainline (if there had been any thought to that --
> though I don't think there was, because I now realize that I don't think
> many had even seen my prior Jan 25th message !) until further testing
> was performed.
> 
> - Mauro replied believing that this was unrelated to anything v4l-dvb,
> but rather an artefact of the X drivers. I suspected that that was NOT
> the case (the nv driver failing in my previous test was my cue). The
> next obvious test was to revert back to an older v4l-dvb snapshot that
> was patched with Mike Krufky's hack/workaround.

It took me some time today to bisect and trying to see what's going wrong with
some userspace apps. 

At the end, I discovered that changeset 10240 fixes a bug that affected some
userspace bad behaviour of setting defaults to zero, if a control is not found.

Due to that userspace bad behaviour, both tvtime and xawtv were using 0 for all
video controls (brightness, contrast, color, hue). The practical effect is that
a black image were displayed.

The fix were as simple as putting all controls at 50%.

Could this be your case also?

Cheers,
Mauro