Re: [PATCH 0/3] media/drx39xyj: fix DJH_DEBUG path null pointer dereferences, and compile errors.

[Mauro Carvalho Chehab]

Hi Devin,

Em Fri, 28 Feb 2014 19:13:16 -0500
Devin Heitmueller <dheitmueller@xxxxxxxxxxxxxx> escreveu:

> Seems kind of strange that I wasn't on the CC for this, since I was the
> original author of all that code (in fact, DJH are my initials).
> 
> Mauro, did you strip off my authorship when you pulled the patches from my
> tree?

Thanks for warning me about that!

Not sure what happened there. The original branch were added back in 2012,
with the sole reason to provide a way for Patrick Dickey to catch a few
patches I made on that time with some CodingStyle fixes:
	http://git.linuxtv.org/mchehab/experimental.git/shortlog/refs/heads/drx-j

There, your name was there as an extra weird "Committer" tag on those changesets:
	http://git.linuxtv.org/mchehab/experimental.git/commit/24d5ed7b19cc19f807264d7d4d56ab48e5cab230
	http://git.linuxtv.org/mchehab/experimental.git/commit/0440897f72b9cf82b8f576fae292b0567ad88239

The second one also contained a "Tag: tip" on it. So, I suspect that
something wrong happened when I imported it (either from your tree or
from some email sent by you or by Patrick). Probably, some broken
hg-import scripting.

Anyway, I rebased my tree, fixing those issues, at:
	http://git.linuxtv.org/mchehab/experimental.git/shortlog/refs/heads/drx-j-v3

I also added a credit at the first patch for Patrick's fixes that
I suspect it was merged somehow there, based on the comments he
posted at the mailing list when he sent his 25-patches series:
	https://lwn.net/Articles/467301/

Please let me know if you find any other issues on it. Anyway, I'll post
the patches from my experimental branch at the ML before merging them
upstream, in order to get a proper review.

Before that happen, however, I need to fix a serious bug that is
preventing to watch TV with this frontend, that it is there since the
first patch.

To be sure that this is a driver issue, I tested the driver on
another OS using the original PCTV driver, and it worked.

However, since the first working version of this driver, it
is randomly losing MPEG TS packets.

The bug is intermittent: every time it sets up VSB reception, it loses
different MPEG TS tables. Sometimes, not a single TS packet is received,
but, most of the time, it gets ~ 1/10 of the expected number of packets.

It behaves like letting a hardware PID filtering on some random state,
inspecting the traffic using dvbv5-zap at monitor mode shows just a
small set of the MPEG TS PIDs,  but I'm starting to suspect that it
could be due to something else, like an improper ISOC setting at em28xx
or due to some clock initialized with the wrong value.

I'm even tried to compare what's the original driver is doing with the
Linux one, but the original driver provided by PCTV was compiled using a
different firmware version, so it uses a different drxj_map.h.

I would need to get in hands the drxj_map.h used by PCTV, in order to be
able to properly see what initialization is being done by the PCTV driver
and see what sequence is missing.

I won't be merging this driver upstream while this bug is not fixed.

It would help a lot if I could get the original tree you worked with, as
maybe this bug might not be present there. In such case, then the bug is
likely at em28xx side.

Do you still have a copy of your old hg tree? Do you have some contact at
PCTV that could help me either getting a binary driver using the same
version as the one you used here, or getting me the newer drxj_map.h
file?

Thanks,
Mauro

> 
> The patches themselves look sane, and I will send a formal Acked-by once I
> can get in front of a real computer.
> 
> Devin
> On Feb 28, 2014 4:23 PM, "Shuah Khan" <shuah.kh@xxxxxxxxxxx> wrote:
> 
> > This patch series fixes null pointer dereference boot failure as well as
> > compile errors.
> >
> > Shuah Khan (3):
> >   media/drx39xyj: fix pr_dbg undefined compile errors when DJH_DEBUG is
> >     defined
> >   media/drx39xyj: remove return that prevents DJH_DEBUG code to run
> >   media/drx39xyj: fix boot failure due to null pointer dereference
> >
> >  drivers/media/dvb-frontends/drx39xyj/drxj.c | 31
> > ++++++++++++++++++-----------
> >  1 file changed, 19 insertions(+), 12 deletions(-)
> >
> > --
> > 1.8.3.2
> >
> > --
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> >


-- 

Cheers,
Mauro
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