-----Original Message----- From: Andres Freund [mailto:andres@anarazel.de] Sent: Monday, September 17, 2012 7:29 AM To: LKML; Deucher, Alexander; David Airlie; dri-devel@lists.freedesktop.org Subject: radeon: Regression between v3.6-rc4 and v3.6-rc6: unable to allocate a PPLL
Hi,
While debugging another issue I upgraded from v3.6-rc4 to latest git (which exactly is v3.6-rc6). After X started up one of my three monitors blacked out. A look into the kernel log revealed: [drm:radeon_atom_pick_pll] *ERROR* unable to allocate a PPLL
What 3 monitors are you using (DVI, HDMI, DP, VGA)? Note that there are only 2 PLLs for non-DP monitors, so if you are trying to use more than 2 non-DP monitors, it's not supported right now and if it worked before, it was random luck. If you want to use 3+ monitors, only 2 can be non-DP, the rest need to be DP. If you use a DP to DVI/HDMI adapter, it must be active (looks like DP to the GPU), passive adapters just pass through native DVI/HDMI. That said, I've got a set of patches for 3.7 to allow PLL sharing properly for non-DP displays, but it's too invasive for -fixes.
Alex