I installed arch linux with kernel 3.8.7 on my mbpro 8,2 and i boot it from EFISTUB directly from rEFInd. These are the parameters passed to the kernel rootflags=,relatime,data=ordered rootfstype=ext4 add_efi_memmap elevator=noop vt.handoff=7 i915.modeset=1 radeon.modeset=1 initrd=\EFI\arch\initramfs-arch.img ro Early boot: cat /sys/kernel/debug/vgaswitcheroo/switch 0:DIS:+:Pwr:0000:01:00.0 1:DIS-Audio: :Pwr:0000:01:00.1 2:IGD: :Pwr:0000:00:02.0 To get a working X server cat /sys/kernel/debug/vgaswitcheroo/switch 0:DIS:+:Pwr:0000:01:00.0 1:DIS-Audio: :Pwr:0000:01:00.1 2:IGD: :Off:0000:00:02.0 any combination od IGD DIGD with or without OFF/ON before and after cause a black screen, The system is fully operational, i can blindly enable radeon by passing DIS to switch and i can get the screen back!
Created attachment 99531 [details] DMESG
I'm affected by the same issue. Is there any possible fix for this ?
I have the same issue. According to an exchange on the rh bz https://bugzilla.redhat.com/show_bug.cgi?id=837461 what is missing is LVDS reprobe from the intel drivers. This issue is also listed https://bugs.freedesktop.org/show_bug.cgi?id=61115 The cause appears to be that on switch, when the intel GPU is connected to the gmux, the display bus is not probed for what is now attached. Thus, the black screen as the intel tries to render to "some other display".
Have you tried 3.11 or 3.12 kernels?
Yes, I'm experiencing the same problem on Archlinux, kernel 3.12.1. My laptop is a Sony Vaio SA series with hardware GPU switch. The systems always starts with the Intel GPU enabled and active. When switching to the dedicated ATI card I get a blank screen. How may I help debug this? I'd really like to use the dedicated card, and there's no way, apart from using the proprietary Catalyst drivers, to enable the ATI card.
I've just updated to ubuntu 14.04 beta 2, which uses kernel 3.13.0-24-lowlatency. This issue is till present. Is there any hope with this issue ? Would love not having to reboot when wanting to use an external screen... makes linux look bad in conferences and presentations... :-(
Same/similar issue here, Arch Linux, kernel 3.14.5, Thinkpad T430 (two muxless cards: NVS 5400M, Intel 4000). When I boot with the Nvidia switched on in /etc/tmpfiles.d: w /sys/kernel/debug/vgaswitcheroo/switch - - - - DDIS w /sys/kernel/debug/vgaswitcheroo/switch - - - - ON the screen attached to the Intel card is black. I see in the logs "i915: switched off". After X started I can write "ON" to /sys/kernel/debug/vgaswitcheroo/switch and the screen attached to the Intel card is working. This bug report has the status NEEDINFO. What info do you need?
https://bugs.freedesktop.org/show_bug.cgi?id=61115
A patchset which is believed to fix this issue was posted to dri-devel: http://lists.freedesktop.org/archives/dri-devel/2015-April/081515.html This patchset enables GPU switching and should at least work on pre-retinas. Please apply it on top of a recent kernel and report back if it works for you. Thank you!