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

[Alex Deucher]

On Thu, Sep 27, 2012 at 9:23 AM, Andres Freund <andres at anarazel.de> wrote:
> On Thursday, September 27, 2012 03:14:31 PM Alex Deucher wrote:
>> 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?
> Yes, but just setting the xrand positions:

Thanks.  I can't seem to reproduce it here, but I've pushed an updated
drm-next-3.7-wip which may help.  If not, can you apply the attached
patch and send me the output?

Thanks,

Alex
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