Re: 3.15.0-rc2 radeon HD 7480D [Aruba] blank display

[Ken Moffat <zarniwhoop@ntlworld.com>]

On Mon, Apr 21, 2014 at 04:54:15PM -0400, Alex Deucher wrote:
> On Mon, Apr 21, 2014 at 4:32 PM, Ken Moffat <zarniwhoop@ntlworld.com> wrote:
> >  I've just built 3.15.0-rc2 on this box, and discovered that I get a
> > blank screen.  The boot appears to complete (it sends me information
> > from SMART which is from my last bootscript), and it responds to
> > MagicSysRQ to reboot.  I tried to login and run startx, but that
> > didn't seem to make any difference - possibly something went wrong,
> > it wasn't in my history when I booted a good kernel.
> >
> >  This machine uses a regular old VGA cable to connect it, the
> > following lines in dmesg make me think it has chosen the wrong
> > connector:
> 
> VGA is implemented as a DP to VGA bridge on APUs.
> 
> >
> > Apr 21 19:32:45 bluesbreaker kernel: [    1.273246]
> > [drm:radeon_dp_link_train_cr] *ERROR* displayport link status failed
> > Apr 21 19:32:45 bluesbreaker kernel: [    1.273247]
> > [drm:radeon_dp_link_train_cr] *ERROR* clock recovery failed
> > Apr 21 19:32:45 bluesbreaker kernel: [    1.295116] Console:
> > switching to colour frame buffer device 85x34
> >
> >  On a boot with 3.14.0 and earlier I get a different console size -
> > Apr 21 20:42:44 bluesbreaker kernel: [    1.445992] Console:
> > switching to colour frame buffer device 133x54
> >
> >  My console font is 12x22, and my screen is 1600x1200 but it looks
> > as if 3.15-rc2 has fallen back to trying to use 1024x768.
> >
> >  I'm attaching what look like the relevant parts of the messages
> > from the system logs for 3.15-rc2 and 3.14.0.
> >
> >  Any ideas, please ?  This is an AMD A4-5300 APU and not the world's
> > fastest machine for bisecting :-(
> 
> I'd guess it's either the pll rework patches or the switch to the
> common dp helper code patches.  It would be helpful if you could
> bisect.
> 
> Alex

 OK, I guess I can do the builds on a faster machine.

ĸen
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