Arch Linux

pcdragon

Member

Registered: 2012-04-11

Posts: 8

[SOLVED] Kernel 3.3.1 CPU usage (DVB / Hauppage)

Hi

I've only been using Arch for a few weeks and loving it so far (after 13 years of Mandrake -> Mandriva -> Mageia). 

A few days ago I did a system upgrade which included new kernel and nvidia packages. After rebooting into the new kernel 3.3.1 I immediately noticed that the CPU usage was up and discovered that a kernel process named "kdvb-ad-0-fe-0" was using 31-37%.  I could not kill that process but stopping mythbackend stops it which is no help at all since I use mythtv daily - so I rolled back the kernel and nvidia (and virtualbox). Everything was back to normal.

Today I looked at a system upgrade again and noticed that mythtv was also in the list so was hopeful that perhaps the new kernel with the new mythtv packages might solve the CPU usage problem - but no luck, same problem exists.

Other than roll back the kernel (and nvidia and virtualbox and ???) does anyone have any suggestions?  Thanks.

[EDIT]
Oops I should mention:

• with mythbackend running on the old kernel (3.2.13-1) it uses only 0-2%

• capture card is Hauppauge WinTV HVR-3000

• kernel drivers are cx88*

I am thinking about filing a bug report so I'll go read up on how to do so correctly.  In the meantime I'll have to try to rollback because my tv programs start in about 3 hours.
[/EDIT]

Last edited by pcdragon (2012-04-14 04:07:28)

pcdragon

Member

Registered: 2012-04-11

Posts: 8

Re: [SOLVED] Kernel 3.3.1 CPU usage (DVB / Hauppage)

OK its not just CPU usage, watching tv is not working properly - picture and sound is choppy and not watchable at all.

litemotiv

Forum Fellow

Registered: 2008-08-01

Posts: 5,026

Re: [SOLVED] Kernel 3.3.1 CPU usage (DVB / Hauppage)

Could you change your topic title to something like:

"Kernel 3.3.1 CPU usage (DVB / Hauppage)"

To better inform readers about the scope of the problem?

Thanks.

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ᶘ ᵒᴥᵒᶅ

pcdragon

Member

Registered: 2012-04-11

Posts: 8

Re: [SOLVED] Kernel 3.3.1 CPU usage (DVB / Hauppage)

Sure... done.

tr0nic

Member

From: Europe

Registered: 2005-05-02

Posts: 15

Re: [SOLVED] Kernel 3.3.1 CPU usage (DVB / Hauppage)

Hi,

I can confirm choppy DVB playback on kernel 3.3.1.
I have a ds3000 based DVB-S card however - it's a TeVii S470 PCI-E.

So I guess this is a kernel bug...

sultanoswing

Member

Registered: 2008-07-23

Posts: 317

Re: [SOLVED] Kernel 3.3.1 CPU usage (DVB / Hauppage)

My Hauppauge HVR-2210 is running fine on 3.3.1 under myth 0.25pre. No chop, no significant CPU use.

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Arch on: ASUS Pro-PRIME x470, AMD 5800X3D, AMD 6800XT, 32GB, | ThinkPad X1 | ASUS ux303ua | Surface Laptop 2 | Minisforum UM780

tr0nic

Member

From: Europe

Registered: 2005-05-02

Posts: 15

Re: [SOLVED] Kernel 3.3.1 CPU usage (DVB / Hauppage)

I'm using kaffeine for DVB playback.
Everything's OK though with kernels prior to 3.3.

I'll stick with linux-lts until we find out what's causing this.

pcdragon

Member

Registered: 2012-04-11

Posts: 8

Re: [SOLVED] Kernel 3.3.1 CPU usage (DVB / Hauppage)

SOLVED:
It turns out that  the variable 're_tune' in /drivers/media/dvb/dvb-core/dvb_frontend.c is not initialized correctly.  I found a patch mentioned here - which I didn't actually apply, I just edited the source file to add the single line and compiled the linux-ck kernel (and nvidia-ck).

CPU usage is back to 0-2% and I can watch TV again! 

It doesn't seem to be mentioned anywhere at kernel.org, perhaps the patch is not accepted???