Re: [v4l-dvb-maintainer] [GIT PATCHES] V4L/DVB updates

CIJOML wrote:
Dne pondělí 16 duben 2007 17:34 Michael Krufky napsal(a):

Adrian Bunk wrote:

On Sun, Apr 15, 2007 at 08:33:38PM -0400, Michael Krufky wrote:

Mauro,

I've been out of town for the past few days... I just got home and saw
this:

Mauro Carvalho Chehab wrote:

- Fix 1/3 for bug 7819: fixed frontend hotplug issue
- Fix 2/3 for bug 7819: demux and dvr
- Fix 3/3 for bug 7819: fixed hotplugging for dvbnet

I don't think that this is 2.6.21 material. These patches have not yet
received
enough testing to be sent to mainline.

I have tested them, and they seem to work for my cxusb device, but we
have yet to hear test results from users of usb dvb devices that do not
use the dvb-usb framework. (ttusb, flexcop-usb, cinergyT2, for example)

The bug that these patches fix has been around throughout the entire
kernel history of the dvb subsystem. The bug is not a regression -- it
has always been
there. In my opinion, it is too late in 2.6.21 development to apply
this change.
Because these fixes are not obvious, I think we should let them get some
more testing, and have them queued for 2.6.22 .

Unless I misunderstand anything, this should fix [1].

And this is a bug that was reported to be present in 2.6.21-rc but not
in 2.6.20 (and it's therefore a regression, no matter whether the
underlying problem was older and only exposed by some other change).

Not true. The DVB subsystem has NEVER been hot-unpluggable. I confirm
that the patches SEEM to be correct, but this has not yet been verified.
None of the authors of dvb-core gave their ACK on these changesets.

The DVB hotplug issue has been around since the very beginning. I assure
you, that I consider this fix to be very important, and I really would love
to see it hit mainline. However, given the situation, it is not
appropriate to push these in during -rc7

I have doubts on CIJOML's testing method -- there is no way he could have
unplugged the device while in use, while running 2.6.20.y and not receive
an OOPS. CIJOML, please see the bottom of this email for

Sure, this will prevent an OOPS on some, and hopefully all devices... but
what if it causes a regression for those untested?

Why do we have a merge window, if new changesets are going to be rushed
into late -rc kernels without proper testing, and without the ack of a dvb
subsystem maintainer?

Are we prepared to go for another -rc and 3 or 4 weeks of testing to
confirm that this fix doesn't cause new regressions? I don't think so.

Markus Rechberger wrote:

The patch has been around on the dvb mailinglist ([PATCH][RFC] DVB
Hotplug Fix, 5. April 2007),

The patch was merged into the development repository at the same time the
pull request was issued to Linus. This has NOT been tested on a wide
scale. It should go to -mm for a while before being merged to mainline.

Mauro Carvalho Chehab wrote:

I also explicitly warned at DVB ML that I were about to send this patch,
together with other fixes, asking the community for more tests. After
that, I received two positive answers on my mailbox from people that
tested and noticed that this really fixed the issue.

One of those positive answers was me - I explained that it worked for me,
but we need others to test.

You waited ONE DAY after sending this "warning" to the dvb mailing list? (
http://linuxtv.org/pipermail/linux-dvb/2007-April/017204.html ) I saw that
email after seeing the pull request to Linus. We dont have users testing
the repositories after each commit -- you _really_ need to give some more
time to allow for such testing.

CIJOML wrote:

Hi,

I have tested these patches with:

Freecom DVB-T dongle
Pluto2 pcmcia card
Leadtek WinFast DTV dongle 1st generation
Leadtek WinFast DTV dongle 2nd generation

These are 4 different devices with 4 different hw and modules.
All works. Please apply.

Well, that helps... But it would still be nice to hear test results on a
CinergyT2 or flexcop-usb.

Which driver supports those Winfast dongles? We already know for sure that
the patches work correctly for any driver based on the dvb-usb framework.

If you had the device open, and then disconnect it from the usb bus, no
matter what kernel version you're running, you should hit the OOPS. I
confirm that these patches prevent that OOPS from occurring, but I have
trouble believing that you did NOT experience such an OOPS in 2.6.20.y

Could you please describe the method in which your test caused an OOPS
using 2.6.21-rc and did NOT cause an oops in 2.6.20.y ?


Hi,

I have tested these patches with 2.6.20-mh1 + v4l-dvb-b5be3479f070 patchset.
I also tried 2.6.21-rc6 + v4l-dvb-b5be3479f070 patchset and this combination
also works without OOPS.

Yes, that shows that the changesets prevent the oops, but it says
nothing about vanilla 2.6.20.y
Winfast dongles are both dvb-usb based (DiBcom 3000M-C and DiBcom DiB7000P),
but pluto2 is cardbus (pci) based.

just as I figured. The pluto2 test results are great to hear, though --
thank you.
I think we can include these patches into 2.6.21 and if we receive any
problem, we still have 2.6.21.Z for fixing, don't we?

The stable kernel series is not there for that purpose. It is not there
to encourage a rush of patches into a final kernel release, only to
cause potential problems, with the 2.6.x.y series as a fallback for
fixes. We should avoid the need for such last-minute fixes wherever
possible.

--
Michael Krufky


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Relevant Pages

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  • Re: [v4l-dvb-maintainer] [GIT PATCHES] V4L/DVB updates
    ... I have tested these patches with: ... Leadtek WinFast DTV dongle 1st generation ... Fix 3/3 for bug 7819: ...
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  • Re: [v4l-dvb-maintainer] [GIT PATCHES] V4L/DVB updates
    ... Fix 3/3 for bug 7819: ... The bug that these patches fix has been around throughout the entire ... Sure, this will prevent an OOPS on some, and hopefully all devices... ...
    (Linux-Kernel)
  • Re: [v4l-dvb-maintainer] [GIT PATCHES] V4L/DVB updates
    ... Fix 3/3 for bug 7819: ... The bug that these patches fix has been around throughout the entire ... Sure, this will prevent an OOPS on some, and hopefully all devices... ...
    (Linux-Kernel)
  • Re: [v4l-dvb-maintainer] [GIT PATCHES] V4L/DVB updates
    ... Fix 3/3 for bug 7819: ... The bug that these patches fix has been around throughout the entire kernel ... The DVB subsystem has NEVER been hot-unpluggable. ... Sure, this will prevent an OOPS on some, and hopefully all devices... ...
    (Linux-Kernel)
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