On Jun 28, 2011, at 6:32 PM, Andy Walls wrote:

> On Tue, 2011-06-28 at 17:39 -0400, Jarod Wilson wrote:
> 
>> Up and running on 3.0-rc5 now, and I'm not seeing the panic, but the
>> box keeps hard-locking after some number of keypresses. Can't get a
>> peep out of it with sysrq, nmi watchdog doesn't seem to fire, etc.
>> 
>> At the suggestion of "Dark Shadow", I've also tried booting the box
>> with pci=nomsi. Works a treat then. Since his HVR-1270 and my HVR-1250
>> both behave much better with pci=nomsi, I'm thinking that in the
>> short-term, we should probably make sure msi doesn't get enabled in
>> the cx23885 driver, and longer-term, we can look at fixing it.
> 
> Sounds fine.  But fixcing the cx23885 driver to deal with both PCIe
> emulation of legacy PCI INTx and PCIe MSI will likely be very involved.
> (Maybe I'm wrong?)

I'm not sure either, but I know a few PCI gurus at work who could
probably lend some insight.


> Taking a trip down memory lane to 2 Dec 2010...
> http://www.spinics.net/lists/linux-media/msg25956.html

Man. I really gotta learn to search the list archive (and bugzillas
assigned to me...) before sending mail to the list, eh? ;)


> On Wed, 2010-12-01 at 21:52 -0800, David Liontooth wrote:
>> On 11/29/2010 04:38 AM, Andy Walls wrote:
>>> On Sun, 2010-11-28 at 23:49 -0800, David Liontooth wrote:
> 
>>> For a quick band-aid, use "pci=nomsi" on your kernel command line, and
>>> reboot to reset the CX23888 hardware.
>>> 
>>> The problem is MSI.  The cx23885 driver isn't ready for it.  The patch
>>> that enabled MSI for cx23885 probably needs to be reverted until some of
>>> these issues are sorted out.
> 
>> -- what do we lose by removing the MSI support patch?
> 
> Problems mostly. The driver was written to work with emulated legacy PCI
> INTx interrupts, which are to be treated as level triggered, and not
> PCIe MSI, which are to be treated as edge triggered.  That's why I say
> the cx23885 driver isn't ready for MSI, but I'm not sure how involved an
> audit and conversion would be.  I know an audit will take time and
> expertise.

Dropping msi support looks to be quite trivial, I got the card behaving
after only a few lines of change in cx23885-core.c without having to pass
in pci=nomsi, but I *only* tried IR, I haven't tried video capture. I'll
see if I can give that a spin tomorrow, and if that behaves, I can send
along the diff. If we wanted to get really fancy, I could add a modparam
to let people turn msi back on. (Never had a single issue with this card
recording with msi enabled, only IR seems busted).

Just had another thought though... I have an HVR-1800 that *does* have
issues recording, and the way the video is corrupted, its possible that
its msi-related... Will have to keep that in mind next time I poke at it.

-- 
Jarod Wilson
ja...@wilsonet.com



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