[ANNOUNCE] xf86-video-intel

Jonathan Miles jon at cybus.co.uk
Thu Apr 16 04:34:11 PDT 2009

On 15/04/09 19:41 Carl Worth said the following:
> On Wed, 2009-04-15 at 09:29 +0100, Jonathan Miles wrote:

> There's not supposed to be anything else required for tear-free XV. So
> something is going wrong. You might be happy (or not) to know that
> you're not the first to hit this bug. See the report here where we're
> trying to diagnose this problem:
> https://bugs.freedesktop.org/show_bug.cgi?id=21076

Yes, I started following this bug recently...

> I haven't been able to replicate this problem myself, (I get tear-free
> XV on both a 945GM and a GM965).

In that case, how can I help? I didn't realise you weren't able to 
reproduce it. I could follow your instructions to check whether or not 
I'm seeing the same as values as the bug submitter. Or if it would help, 
I could probably get a kernel debugger hooked up later (bearing in mind 
that I've never tried this with a USB serial dongle on a laptop).

> Behavior with tearing in the same place consistently is very odd. And
> that almost suggests to me that something other than our driver code in
> i830_video.c is trying to sync. (Do you a compositing manager running
> perhaps?) The reason I say that is that in and earlier, our
> driver was syncing to vertical retrace for tear-free video. But, to fix
> a bug, (GPU hang when screensaver activated during XV syncing), I
> changed the driver to not sync on vertical retrace. Instead we get
> tear-free video now by waiting only until the refresh is outside the
> current window. So I wouldn't expect that code to ever give you any
> consistent tearing.

Okay, understood... that is strange. I am using Compiz (0.8.2 + whatever 
Ubuntu patches it with).

I'm going to pull the latest git trees later and start looking into this 
in more detail.



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