radeon: Regression between v3.6-rc4 and v3.6-rc6: unable to allocate a PPLL

[Alex Deucher]

On Thu, Sep 27, 2012 at 2:46 AM, Andres Freund <andres at anarazel.de> wrote:
> On Wednesday, September 26, 2012 03:42:40 PM Deucher, Alexander wrote:
>> > -----Original Message-----
>> > From: Andres Freund [mailto:andres at anarazel.de]
>> > Sent: Wednesday, September 26, 2012 9:41 AM
>> > To: Dan Carpenter
>> > Cc: Deucher, Alexander; LKML; David Airlie;
>> > dri-devel at lists.freedesktop.org Subject: Re: radeon: Regression between
>> > v3.6-rc4 and v3.6-rc6: unable to allocate a PPLL
>> >
>> > On Wednesday, September 26, 2012 03:00:09 PM Dan Carpenter wrote:
>> > > This is fixed now?
>> >
>> > Its been reverted in 2f1f4d9b60396d2df4cff829bd5376ffc8ed9a2c which is in
>> > rc6.
>> >
>> > On Monday, September 17, 2012 09:30:12 PM Deucher, Alexander wrote:
>> > Sorry, I somehow accidentally marked your  email as read and thus didn't
>> > notice it.
>> >
>> > > I think I see the problem.  I think it's a limitation of the current
>> > > current
>> >
>> > modesetting API.  The current API sets up each display independently
>> > which doesn't work so well if there are resource restrictions.  There
>> > shouldn't be any contention on your board since you are only using 2
>> > non-DP displays.  It looks like X is mapping different crtcs to displays
>> > than the kernel fb.
>> >
>> > Initially the kernel set up the follow:
>> > > > [    2.134901] [drm] crtc 0 using pll 0x2
>> > > > [    2.362257] [drm] crtc 1 using pll 0x1
>> > > > [    2.386709] [drm] crtc 2 using pll 0x0
>> > >
>> > > Crtc 0 -> DCPLL -> DP
>> > > Crtc 1 -> PPLL2 -> DVI
>> > > Crtc 2 -> PPLL1 -> DVI
>> > >
>> > > When X loads, it tried to set a different crtc to display mapping:
>> > > > [   60.679310] [drm] crtc 0 using pll 0xff
>> > > > [   60.789183] [drm] crtc 1 using pll 0x2
>> > > > [   60.819594] [drm] crtc 2 using pll 0x1
>> > >
>> > > Crtc 0 -> INVALID -> DVI 0
>> > > Crtc 1 -> DCPLL -> DP
>> > > Crtc 2 -> PPLL2 -> DVI 1
>> > >
>> > > Crtc 0 should have used PPLL1 or PPLL2, but they were already in use by
>> > > crtc 1 and crtc  2 from the previous modeset.  Since the modeset API is
>> > > not atomic, it doesn't have the whole picture.  I'm not sure of a good
>> > > solution right now prior to the new atomic modeset API that is under
>> > > discussion.  I guess we can revert the patch for 3.6.  For 3.7 I guess
>> > > we need to validate the actual connector to make sure we aren't trying
>> > > to set a different configuration relating to the same connector
>> > > without first tearing down the first one.  In the interim, you should
>> > > be able to work around it by disabling the non-DP outputs and then
>> > > bringing than back up.
>> >
>> > Thanks! That explanation makes sense. I can work around it just fine,
>> > starting X multiple times works which coincides nicely with your
>> > explanation.
>> >
>> > The code in the 3.7 branch doesn't do that extended validation yet,
>> > rigth? If you want/need you can CC for testing once thats ready.
>>
>> It should handle it now.  If you could test it that would be great.
> Ok, just to be sure I tested Linus' tree and everything works fine there.
>
> Unfortunately thats not the case with a straight merge of alexdeucher/drm-
> next-3.7-wip. When gdm started *the first time* the DVI-connected (uhm, same
> sink type? Thats the saphire magic allowing more monitors on that type of
> graphics card?) I got a "unable to allocate a PPLL" error again. Logging
> in/starting a new X seems to fix that.

So you have a xorg.conf with a hardcoded configuration?  If so can you
send it to me?

Thanks,

Alex