Re: [linux-dvb] [RFC] video-buf redesign

2007-09-26 Thread hermann pitton
Hi,

Am Mittwoch, den 26.09.2007, 11:25 -0400 schrieb [EMAIL PROTECTED]: 
 Mauro Carvalho Chehab wrote:
  Unfortunately, I see the same broken behavior in the videobuf tree and
  the tm6000-new tree.  Only the master branch v4l-dvb tree is
  functioning properly.
  
 
  Unfortunately, there's nothing I can do without the logs. So, _please_
  send the logs also.
 
  Every test I did here (and also Hermann reports) didn't produce the
  issues you're showing. 
 
  All I get here is clean mpeg streams, with videobuf-dvb and cx88-dvb.
 
  There is, however, a known issue with IRQ and SMP machines that might be
  influencing. So, I need you to do also cat /proc/cpuinfo. If the
  machine you're using to test has more than one CPU core, you may also
  need to run irqbalance. Another valuable test would be to disable the
  second core, and see what's happening.

I also conducted the tests only on UP machines on the saa7134 driver.

 Mauro,
 
 It is a dual-core CPU.  This should be irrelevant to the issue, since 
 multi-core CPU's have no problem when using the videobuf code in the 
 master branch -- why would your new videobuf code be dependent on a 
 single core when the original videobuf code was not?
 
 I had previously sent you logs of this problem while using read() , but 
 you said this was not good enough -- You told me that the logs did not 
 indicate any errors.
 
 The only way to test this without using read() would be to use xawtv4, 
 which I am not able to build on my Ubuntu Feisty system.  Otherwise, I 
 could try to test by installing mythtv-backend, but that will take a lot 
 of time to setup -- I'll be happy to do it after I've settled in the new 
 apartment, if need be.
 
 I understand that neither you nor Hermann were able to reproduce this 
 problem, but I assure you, this is indeed a regression, and it's a 
 show-stopper for 2.6.24 -- it absolutely must be fixed prior to a merge.

Yes, I agree then. We should be careful with this small testing base we
have and Mike obviously noticed issues.

 I will not be able to conduct any more tests until after I unpack into 
 my new apartment (next week) -- I will take down this test machine 
 tonight and pack it up in boxes.
 
 If you still would like to see logs while using read() , then I can do 
 this tonight before I pack up the test machine.  If you want these logs, 
 please let me know asap.

Unfortunately I have not even a DVB-T card currently ...
The Medion Quad I ordered isn't here yet, also unsure if I can get DVB-T
running on it, don't have the original green PCI Slot for it.
Else I considered to get the Asus P7131 Hybrid LNA, since Soeren still
reports issues on it, also memory corruption with the old stuff.
http://linuxtv.org/pipermail/linux-dvb/2007-September/020748.html

This is still the only such report within the last two years.

The only case I know from Hartmut that this could happen, also tested
myself, is if someone uses DVB-T and anlog video at once from external
inputs with planar formats, like mplayer/mencoder does by default and
not packed formats as advised in such case.

Why this happens on his machine with VDR and an additional saa7146
device, I still don't know. We have also no reports for the new
video_buf design from saa7146 users.

Just installed the tm6000-new tree on two machines again and xawtv4
seems to be fine on both, UP, no DVB-T currently, no HD streams.

Cheers,
Hermann



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Re: [linux-dvb] [RFC] video-buf redesign

2007-09-26 Thread Mauro Carvalho Chehab

Em Qua, 2007-09-26 às 22:58 +0200, hermann pitton escreveu:
 Hi,
 
 Am Mittwoch, den 26.09.2007, 11:25 -0400 schrieb [EMAIL PROTECTED]: 
  Mauro Carvalho Chehab wrote:
   Unfortunately, I see the same broken behavior in the videobuf tree and
   the tm6000-new tree.  Only the master branch v4l-dvb tree is
   functioning properly.
   
  
   Unfortunately, there's nothing I can do without the logs. So, _please_
   send the logs also.
  
   Every test I did here (and also Hermann reports) didn't produce the
   issues you're showing. 
  
   All I get here is clean mpeg streams, with videobuf-dvb and cx88-dvb.
  
   There is, however, a known issue with IRQ and SMP machines that might be
   influencing. So, I need you to do also cat /proc/cpuinfo. If the
   machine you're using to test has more than one CPU core, you may also
   need to run irqbalance. Another valuable test would be to disable the
   second core, and see what's happening.
 
 I also conducted the tests only on UP machines on the saa7134 driver.

My tests with cx88-dvb were with dualcore AMD. I noticed some logs,
indicating that irq handling is not fast enough to handle one irq for
every frame buffer. Yet, my machine were capable of not losing any
frames (this happened on both the current videobuf and the newer one).
Probably, if my machine were a little slow, or if the irq where shared
with some other devices, I would lose frames.

I'll re-run the tests disabling the second CPU and with both running,
but without irqbalance. Let's see.

  I understand that neither you nor Hermann were able to reproduce this 
  problem, but I assure you, this is indeed a regression, and it's a 
  show-stopper for 2.6.24 -- it absolutely must be fixed prior to a merge.
 
 Yes, I agree then. We should be careful with this small testing base we
 have and Mike obviously noticed issues.

Fixing is important.


 Why this happens on his machine with VDR and an additional saa7146
 device, I still don't know. We have also no reports for the new
 video_buf design from saa7146 users.

It may be due to IRQ sharing. If you have two boards receiving
interrupts at the same IRQ line, you may suffer this kind of troubles,
since both drivers will be called, on a serial way, to handle that IRQ
line. This will delay videobuf handling. In this case, a small time
increment at videobuf processing may produce such troubles.

I'm writing a small patch that will reduce a little bit the videobuf
timings. Hopefully, this will fix the issue.
 
 Just installed the tm6000-new tree on two machines again and xawtv4
 seems to be fine on both, UP, no DVB-T currently, no HD streams.

Thanks, Hermann.
 
 Cheers,
 Hermann
 
 
-- 
Cheers,
Mauro


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