On 31.05.2017 14:57, Alex Deucher wrote: > On Wed, May 31, 2017 at 5:21 AM, Lukas Wunner <lukas@xxxxxxxxx> wrote: >> On Wed, May 31, 2017 at 10:48:37AM +0200, Florian Echtler wrote: >> >> Hm, try booting with drm.debug=0xf to see if link training for the >> eDP connector succeeds. If the link cannot be trained, it would >> explain that the screen stays black. Should this indeed be the >> case, one possible explanation would be that the panel is muxed >> to the external port on resume and an appropriate command needs to >> be sent to the SMC to switch the mux to the radeon card. This could >> be done in the ->resume_early hook of your APP000C platform driver. >> The apple-gmux driver contains something similar to power the discrete >> GPU down if it was off before suspend (because the BIOS always powers >> it up on resume). Here's the (substantial) dmesg output, with drm.debug=0xf: http://floe.butterbrot.org/external/radeon/dmesg_after_suspend I haven't been able to find any references to link training, though. >> *shrug* Unfortunately I'm not familiar at all with radeontool. :-( > > You can use the radeonreg tool to dump the display registers: > https://cgit.freedesktop.org/~agd5f/radeontool/ > radeonreg regs dce3 > replace dce3 with whatever dce version your card has. AFAICT the RV730 indeed has dce3, so I created a register dump before and after suspend: http://floe.butterbrot.org/external/radeon/regs_before_suspend.txt http://floe.butterbrot.org/external/radeon/regs_after_suspend.txt The diff, however, is quite large, I have no idea which registers to look for. Best, Florian -- SENT FROM MY DEC VT50 TERMINAL
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