radeon issues on MacBook Pro 8,2

[Seth Forshee]

On Thu, Jan 19, 2012 at 02:48:52PM -0500, Alex Deucher wrote:
> On Thu, Jan 19, 2012 at 12:18 PM, Seth Forshee
> <seth.forshee at canonical.com> wrote:
> > I'm seeing several issues related to the radeon driver on a MacBook Pro
> > 8,2 with the following graphics card:
> >
> >  ATI Technologies Inc Whistler [AMD Radeon HD 6600M Series] [1002:6741]
> >
> > All problems were observed when using kernel version 3.2.1. None are
> > seen when using fglrx.
> >
> >  1. Excessive power draw. When using the radeon driver ACPI reports a
> >    power draw of about 30W on an idle desktop. Using fglrx brings this
> >    number down to 15W.
> 
> The power saving features of the open source driver are not yet as
> good as the closed source driver.  Please see the power management
> section of this page (http://wiki.x.org/wiki/RadeonFeature) for more
> info on the options currently available.

The dynpm option makes a small difference, saving about 2W. I did notice
an ocassional flash on the screen with this option, and the same flash
each time I changed the power options.

The only thing that improves things significatnly is the "low" profile
method, which gets it down to about 18.5W.

> >  2. Occasional long delays when suspending. When this happens I see
> >    messages like following in dmesg:
> >
> >      [drm:atom_op_jump] *ERROR* atombios stuck in loop for more than 5secs aborting
> >      [drm:atom_execute_table_locked] *ERROR* atombios stuck executing D44E (len 62, WS 0, PS 0) @ 0xD46A
> >
> >    Sometimes one of suspend or resume hangs completely, but I can't
> >    tell which and am not sure whether or not it's related. I'm also
> >    testing a Mac Mini with the exact same card which does not seem to
> >    suffer from this issue.
> >
> >    I ran a bisections that identified f8d0edd (drm/radeon/kms: improve
> >    DP detect logic) as introducing problems with suspend, and reverting
> >    this patch on top of 3.2.1 does seem to eliminate both issues.
> >
> 
> That patch doesn't really affect the modesetting paths directly; it
> looks like a red herring to me.

Perhaps. I just started a run of 200 s3 cycles with the patch reverted
to see if I can reproduce the issues. I can usually trigger the problem
with 15 or fewer s3 cycles.

> >  3. When the LVDS panel is powered off and back on, the display
> >    flickers, as if the backlight is cycling rapidly between low and
> >    high brightness. If the panel is left on this effect gradually
> >    lessens and is eventually no longer noticable. This is not seen with
> >    fglrx.
> >
> 
> For the sake of tracking this properly, it would probably be best to file a bug:
> https://bugs.freedesktop.org
> Product: DRI
> Component: DRM/Radeon
> What connectors does your card actually have on it?  Please attach a
> copy of your dmesg output and vbios:
> (as root)
> (use lspci to get the bus id)
> cd /sys/bus/pci/devices/<pci bus id>
> echo 1 > rom
> cat rom > /tmp/vbios.rom
> echo 0 > rom
> 
> Also, keep in mind that this is a mac so it's likely there may be
> wonky mac specific problems.

I filed bug #44955 for the flickering issue.

Thanks,
Seth